diff --git a/FEATURES.md b/FEATURES.md
index 1767c08d..b5d78839 100644
--- a/FEATURES.md
+++ b/FEATURES.md
@@ -28,7 +28,7 @@ Features that are in ***bold italics*** are planned and not yet implemented.
 
 ## Area Selection
 
-- Dropdown to switch area
+- Dropdown menu to switch area
 
 ## Simple Quest Properties
 
@@ -51,6 +51,7 @@ Features that are in ***bold italics*** are planned and not yet implemented.
 - ***Top-down view (orthogonal view might suffice?)***
 - ***Add "shadow" to entities to more easily see where floating entities are positioned***
   - ***MVP: a single line***
+- ***Show positions and radii from the relevant script instructions***
 
 ## NPC/object manipulation
 
diff --git a/src/data_formats/parsing/quest/opcodes.ts b/src/data_formats/parsing/quest/opcodes.ts
index b628343e..0fa3e80b 100644
--- a/src/data_formats/parsing/quest/opcodes.ts
+++ b/src/data_formats/parsing/quest/opcodes.ts
@@ -2922,16 +2922,16 @@ export class Opcode {
         false,
         []
     ));
-    static readonly unknown_f8e6 = (OPCODES[0xf8e6] = new Opcode(
+    static readonly move_coords_object = (OPCODES[0xf8e6] = new Opcode(
         0xf8e6,
-        "unknown_f8e6",
+        "move_coords_object ",
         [{ type: Type.Register }, { type: Type.Register }],
         false,
         []
     ));
-    static readonly unknown_f8e7 = (OPCODES[0xf8e7] = new Opcode(
+    static readonly at_coords_call_ex = (OPCODES[0xf8e7] = new Opcode(
         0xf8e7,
-        "unknown_f8e7",
+        "at_coords_call_ex",
         [{ type: Type.Register }, { type: Type.Register }],
         false,
         []
diff --git a/src/scripting/ValueSet.test.ts b/src/scripting/ValueSet.test.ts
new file mode 100644
index 00000000..93d2365f
--- /dev/null
+++ b/src/scripting/ValueSet.test.ts
@@ -0,0 +1,55 @@
+import { ValueSet } from "./ValueSet";
+
+test("empty", () => {
+    const vs = new ValueSet();
+
+    expect(vs.size()).toBe(0);
+});
+
+test("set_value", () => {
+    const vs = new ValueSet();
+    vs.set_value(100);
+    vs.set_value(4);
+    vs.set_value(24324);
+
+    expect(vs.size()).toBe(1);
+    expect([...vs]).toEqual([24324]);
+});
+
+test("union", () => {
+    const c = new ValueSet()
+        .union(new ValueSet().set_value(21))
+        .union(new ValueSet().set_value(4968));
+
+    expect(c.size()).toBe(2);
+    expect([...c]).toEqual([21, 4968]);
+});
+
+test("union of intervals", () => {
+    const a = new ValueSet()
+        .union(new ValueSet().set_interval(10, 13))
+        .union(new ValueSet().set_interval(14, 17));
+
+    expect(a.size()).toBe(6);
+    expect([...a]).toEqual([10, 11, 12, 14, 15, 16]);
+
+    a.union(new ValueSet().set_interval(13, 14));
+
+    expect(a.size()).toBe(7);
+    expect([...a]).toEqual([10, 11, 12, 13, 14, 15, 16]);
+
+    a.union(new ValueSet().set_interval(1, 3));
+
+    expect(a.size()).toBe(9);
+    expect([...a]).toEqual([1, 2, 10, 11, 12, 13, 14, 15, 16]);
+
+    a.union(new ValueSet().set_interval(30, 33));
+
+    expect(a.size()).toBe(12);
+    expect([...a]).toEqual([1, 2, 10, 11, 12, 13, 14, 15, 16, 30, 31, 32]);
+
+    a.union(new ValueSet().set_interval(20, 22));
+
+    expect(a.size()).toBe(14);
+    expect([...a]).toEqual([1, 2, 10, 11, 12, 13, 14, 15, 16, 20, 21, 30, 31, 32]);
+});
diff --git a/src/scripting/ValueSet.ts b/src/scripting/ValueSet.ts
new file mode 100644
index 00000000..bbac94d3
--- /dev/null
+++ b/src/scripting/ValueSet.ts
@@ -0,0 +1,112 @@
+/**
+ * Represents a set of integers.
+ */
+export class ValueSet {
+    /**
+     * Open intervals [start, end[.
+     */
+    private intervals: { start: number; end: number }[] = [];
+
+    size(): number {
+        return this.intervals.reduce((acc, i) => acc + i.end - i.start, 0);
+    }
+
+    /**
+     * Sets this ValueSet to the given integer.
+     *
+     * @param value integer value
+     */
+    set_value(value: number): ValueSet {
+        this.intervals = [{ start: value, end: value + 1 }];
+        return this;
+    }
+
+    /**
+     * Sets this ValueSet to the values in the given interval.
+     *
+     * @param start lower bound, inclusive
+     * @param end upper bound, exclusive
+     */
+    set_interval(start: number, end: number): ValueSet {
+        if (end < start)
+            throw new Error(
+                `Interval upper bound should be greater than lower bound, got [${start}, ${end}[.`
+            );
+
+        if (end !== start) {
+            this.intervals = [{ start, end }];
+        }
+
+        return this;
+    }
+
+    union(other: ValueSet): ValueSet {
+        let i = 0;
+
+        outer: for (const b of other.intervals) {
+            while (i < this.intervals.length) {
+                const a = this.intervals[i];
+
+                if (b.end < a.start) {
+                    this.intervals.splice(i, 0, b);
+                    i++;
+                    continue outer;
+                } else if (b.start <= a.end) {
+                    a.start = Math.min(a.start, b.start);
+
+                    let j = i;
+
+                    while (j < this.intervals.length) {
+                        if (b.end > this.intervals[j].start) {
+                            a.end = this.intervals[j].end;
+                            j++;
+                        } else {
+                            break;
+                        }
+                    }
+
+                    this.intervals.splice(i + 1, j - i - 1);
+                    a.end = Math.max(a.end, b.end);
+                    i++;
+                    continue outer;
+                } else {
+                    i++;
+                }
+            }
+
+            this.intervals.push(b);
+        }
+
+        return this;
+    }
+
+    [Symbol.iterator](): Iterator<number> {
+        const vs = this;
+        let int_i = 0;
+        let value = NaN;
+
+        return {
+            next(): IteratorResult<number> {
+                let done = true;
+
+                if (int_i < vs.intervals.length) {
+                    if (isNaN(value)) {
+                        value = vs.intervals[int_i].start;
+                        done = false;
+                    } else if (value >= vs.intervals[int_i].end) {
+                        int_i++;
+
+                        if (int_i < vs.intervals.length) {
+                            value = vs.intervals[int_i].start;
+                            done = false;
+                        }
+                    } else {
+                        done = false;
+                    }
+                }
+
+                return { done, value: value++ };
+            },
+        };
+    }
+}
diff --git a/src/scripting/data_flow_analysis.test.ts b/src/scripting/data_flow_analysis.test.ts
index 4f0d0d2e..c0ff4a72 100644
--- a/src/scripting/data_flow_analysis.test.ts
+++ b/src/scripting/data_flow_analysis.test.ts
@@ -9,14 +9,14 @@ test("single instruction", () => {
     `);
     const cfg = create_control_flow_graph(im);
 
-    expect(cfg.nodes.length).toBe(1);
+    expect(cfg.blocks.length).toBe(1);
 
-    expect(cfg.nodes[0].start).toBe(0);
-    expect(cfg.nodes[0].end).toBe(1);
-    expect(cfg.nodes[0].branch_type).toBe(BranchType.Return);
-    expect(cfg.nodes[0].from.length).toBe(0);
-    expect(cfg.nodes[0].to.length).toBe(0);
-    expect(cfg.nodes[0].branch_labels.length).toBe(0);
+    expect(cfg.blocks[0].start).toBe(0);
+    expect(cfg.blocks[0].end).toBe(1);
+    expect(cfg.blocks[0].branch_type).toBe(BranchType.Return);
+    expect(cfg.blocks[0].from.length).toBe(0);
+    expect(cfg.blocks[0].to.length).toBe(0);
+    expect(cfg.blocks[0].branch_labels.length).toBe(0);
 });
 
 test("single unconditional jump", () => {
@@ -28,21 +28,21 @@ test("single unconditional jump", () => {
     `);
     const cfg = create_control_flow_graph(im);
 
-    expect(cfg.nodes.length).toBe(2);
+    expect(cfg.blocks.length).toBe(2);
 
-    expect(cfg.nodes[0].start).toBe(0);
-    expect(cfg.nodes[0].end).toBe(1);
-    expect(cfg.nodes[0].branch_type).toBe(BranchType.Jump);
-    expect(cfg.nodes[0].from.length).toBe(0);
-    expect(cfg.nodes[0].to.length).toBe(1);
-    expect(cfg.nodes[0].branch_labels.length).toBe(1);
+    expect(cfg.blocks[0].start).toBe(0);
+    expect(cfg.blocks[0].end).toBe(1);
+    expect(cfg.blocks[0].branch_type).toBe(BranchType.Jump);
+    expect(cfg.blocks[0].from.length).toBe(0);
+    expect(cfg.blocks[0].to.length).toBe(1);
+    expect(cfg.blocks[0].branch_labels.length).toBe(1);
 
-    expect(cfg.nodes[1].start).toBe(0);
-    expect(cfg.nodes[1].end).toBe(1);
-    expect(cfg.nodes[1].branch_type).toBe(BranchType.Return);
-    expect(cfg.nodes[1].from.length).toBe(1);
-    expect(cfg.nodes[1].to.length).toBe(0);
-    expect(cfg.nodes[1].branch_labels.length).toBe(0);
+    expect(cfg.blocks[1].start).toBe(0);
+    expect(cfg.blocks[1].end).toBe(1);
+    expect(cfg.blocks[1].branch_type).toBe(BranchType.Return);
+    expect(cfg.blocks[1].from.length).toBe(1);
+    expect(cfg.blocks[1].to.length).toBe(0);
+    expect(cfg.blocks[1].branch_labels.length).toBe(0);
 });
 
 test("single conditional jump", () => {
@@ -55,28 +55,28 @@ test("single conditional jump", () => {
     `);
     const cfg = create_control_flow_graph(im);
 
-    expect(cfg.nodes.length).toBe(3);
+    expect(cfg.blocks.length).toBe(3);
 
-    expect(cfg.nodes[0].start).toBe(0);
-    expect(cfg.nodes[0].end).toBe(1);
-    expect(cfg.nodes[0].branch_type).toBe(BranchType.ConditionalJump);
-    expect(cfg.nodes[0].from.length).toBe(0);
-    expect(cfg.nodes[0].to.length).toBe(2);
-    expect(cfg.nodes[0].branch_labels.length).toBe(1);
+    expect(cfg.blocks[0].start).toBe(0);
+    expect(cfg.blocks[0].end).toBe(1);
+    expect(cfg.blocks[0].branch_type).toBe(BranchType.ConditionalJump);
+    expect(cfg.blocks[0].from.length).toBe(0);
+    expect(cfg.blocks[0].to.length).toBe(2);
+    expect(cfg.blocks[0].branch_labels.length).toBe(1);
 
-    expect(cfg.nodes[1].start).toBe(1);
-    expect(cfg.nodes[1].end).toBe(2);
-    expect(cfg.nodes[1].branch_type).toBe(BranchType.Return);
-    expect(cfg.nodes[1].from.length).toBe(1);
-    expect(cfg.nodes[1].to.length).toBe(0);
-    expect(cfg.nodes[1].branch_labels.length).toBe(0);
+    expect(cfg.blocks[1].start).toBe(1);
+    expect(cfg.blocks[1].end).toBe(2);
+    expect(cfg.blocks[1].branch_type).toBe(BranchType.Return);
+    expect(cfg.blocks[1].from.length).toBe(1);
+    expect(cfg.blocks[1].to.length).toBe(0);
+    expect(cfg.blocks[1].branch_labels.length).toBe(0);
 
-    expect(cfg.nodes[2].start).toBe(0);
-    expect(cfg.nodes[2].end).toBe(1);
-    expect(cfg.nodes[2].branch_type).toBe(BranchType.Return);
-    expect(cfg.nodes[2].from.length).toBe(1);
-    expect(cfg.nodes[2].to.length).toBe(0);
-    expect(cfg.nodes[2].branch_labels.length).toBe(0);
+    expect(cfg.blocks[2].start).toBe(0);
+    expect(cfg.blocks[2].end).toBe(1);
+    expect(cfg.blocks[2].branch_type).toBe(BranchType.Return);
+    expect(cfg.blocks[2].from.length).toBe(1);
+    expect(cfg.blocks[2].to.length).toBe(0);
+    expect(cfg.blocks[2].branch_labels.length).toBe(0);
 });
 
 test("single call", () => {
@@ -89,31 +89,31 @@ test("single call", () => {
     `);
     const cfg = create_control_flow_graph(im);
 
-    expect(cfg.nodes.length).toBe(3);
+    expect(cfg.blocks.length).toBe(3);
 
-    expect(cfg.nodes[0].start).toBe(0);
-    expect(cfg.nodes[0].end).toBe(1);
-    expect(cfg.nodes[0].branch_type).toBe(BranchType.Call);
-    expect(cfg.nodes[0].from.length).toBe(0);
-    expect(cfg.nodes[0].to.length).toBe(1);
-    expect(cfg.nodes[0].branch_labels.length).toBe(1);
+    expect(cfg.blocks[0].start).toBe(0);
+    expect(cfg.blocks[0].end).toBe(1);
+    expect(cfg.blocks[0].branch_type).toBe(BranchType.Call);
+    expect(cfg.blocks[0].from.length).toBe(0);
+    expect(cfg.blocks[0].to.length).toBe(1);
+    expect(cfg.blocks[0].branch_labels.length).toBe(1);
 
-    expect(cfg.nodes[1].start).toBe(1);
-    expect(cfg.nodes[1].end).toBe(2);
-    expect(cfg.nodes[1].branch_type).toBe(BranchType.Return);
-    expect(cfg.nodes[1].from.length).toBe(1);
-    expect(cfg.nodes[1].to.length).toBe(0);
-    expect(cfg.nodes[1].branch_labels.length).toBe(0);
+    expect(cfg.blocks[1].start).toBe(1);
+    expect(cfg.blocks[1].end).toBe(2);
+    expect(cfg.blocks[1].branch_type).toBe(BranchType.Return);
+    expect(cfg.blocks[1].from.length).toBe(1);
+    expect(cfg.blocks[1].to.length).toBe(0);
+    expect(cfg.blocks[1].branch_labels.length).toBe(0);
 
-    expect(cfg.nodes[2].start).toBe(0);
-    expect(cfg.nodes[2].end).toBe(1);
-    expect(cfg.nodes[2].branch_type).toBe(BranchType.Return);
-    expect(cfg.nodes[2].from.length).toBe(1);
-    expect(cfg.nodes[2].to.length).toBe(1);
-    expect(cfg.nodes[2].branch_labels.length).toBe(0);
+    expect(cfg.blocks[2].start).toBe(0);
+    expect(cfg.blocks[2].end).toBe(1);
+    expect(cfg.blocks[2].branch_type).toBe(BranchType.Return);
+    expect(cfg.blocks[2].from.length).toBe(1);
+    expect(cfg.blocks[2].to.length).toBe(1);
+    expect(cfg.blocks[2].branch_labels.length).toBe(0);
 });
 
-test("conditional branch with fall-through", () => {
+test("conditional jump with fall-through", () => {
     const im = to_instructions(`
         0:
             jmp_> r1, r2, 1
@@ -124,28 +124,28 @@ test("conditional branch with fall-through", () => {
     `);
     const cfg = create_control_flow_graph(im);
 
-    expect(cfg.nodes.length).toBe(3);
+    expect(cfg.blocks.length).toBe(3);
 
-    expect(cfg.nodes[0].start).toBe(0);
-    expect(cfg.nodes[0].end).toBe(1);
-    expect(cfg.nodes[0].branch_type).toBe(BranchType.ConditionalJump);
-    expect(cfg.nodes[0].from.length).toBe(0);
-    expect(cfg.nodes[0].to.length).toBe(2);
-    expect(cfg.nodes[0].branch_labels.length).toBe(1);
+    expect(cfg.blocks[0].start).toBe(0);
+    expect(cfg.blocks[0].end).toBe(1);
+    expect(cfg.blocks[0].branch_type).toBe(BranchType.ConditionalJump);
+    expect(cfg.blocks[0].from.length).toBe(0);
+    expect(cfg.blocks[0].to.length).toBe(2);
+    expect(cfg.blocks[0].branch_labels.length).toBe(1);
 
-    expect(cfg.nodes[1].start).toBe(1);
-    expect(cfg.nodes[1].end).toBe(2);
-    expect(cfg.nodes[1].branch_type).toBe(BranchType.None);
-    expect(cfg.nodes[1].from.length).toBe(1);
-    expect(cfg.nodes[1].to.length).toBe(1);
-    expect(cfg.nodes[1].branch_labels.length).toBe(0);
+    expect(cfg.blocks[1].start).toBe(1);
+    expect(cfg.blocks[1].end).toBe(2);
+    expect(cfg.blocks[1].branch_type).toBe(BranchType.None);
+    expect(cfg.blocks[1].from.length).toBe(1);
+    expect(cfg.blocks[1].to.length).toBe(1);
+    expect(cfg.blocks[1].branch_labels.length).toBe(0);
 
-    expect(cfg.nodes[2].start).toBe(0);
-    expect(cfg.nodes[2].end).toBe(2);
-    expect(cfg.nodes[2].branch_type).toBe(BranchType.Return);
-    expect(cfg.nodes[2].from.length).toBe(2);
-    expect(cfg.nodes[2].to.length).toBe(0);
-    expect(cfg.nodes[2].branch_labels.length).toBe(0);
+    expect(cfg.blocks[2].start).toBe(0);
+    expect(cfg.blocks[2].end).toBe(2);
+    expect(cfg.blocks[2].branch_type).toBe(BranchType.Return);
+    expect(cfg.blocks[2].from.length).toBe(2);
+    expect(cfg.blocks[2].to.length).toBe(0);
+    expect(cfg.blocks[2].branch_labels.length).toBe(0);
 });
 
 function to_instructions(assembly: string): InstructionSegment[] {
diff --git a/src/scripting/data_flow_analysis.ts b/src/scripting/data_flow_analysis.ts
index e1eeed49..54bb98cb 100644
--- a/src/scripting/data_flow_analysis.ts
+++ b/src/scripting/data_flow_analysis.ts
@@ -1,10 +1,11 @@
 import {
-    Instruction,
     InstructionSegment,
     Opcode,
     Segment,
     SegmentType,
+    Instruction,
 } from "../data_formats/parsing/quest/bin";
+import { ValueSet } from "./ValueSet";
 
 export enum BranchType {
     None,
@@ -36,38 +37,93 @@ export class BasicBlock {
 }
 
 export class ControlFlowGraph {
-    readonly nodes: BasicBlock[] = [];
+    readonly blocks: BasicBlock[] = [];
+    readonly instructions: Map<Instruction, BasicBlock> = new Map();
 }
 
 export function create_control_flow_graph(segments: InstructionSegment[]): ControlFlowGraph {
     const cfg = new ControlFlowGraph();
-    /**
-     * Mapping of labels to basic blocks.
-     */
+    // Mapping of labels to basic blocks.
     const label_blocks = new Map<number, BasicBlock>();
 
     for (const segment of segments) {
-        const blocks = create_basic_blocks(segment);
-
-        if (blocks.length) {
-            cfg.nodes.push(...blocks);
-
-            for (const label of segment.labels) {
-                label_blocks.set(label, blocks[0]);
-            }
-        }
+        create_basic_blocks(cfg, label_blocks, segment);
     }
 
     link_blocks(cfg, label_blocks);
     return cfg;
 }
 
-function create_basic_blocks(segment: InstructionSegment): BasicBlock[] {
-    const blocks: BasicBlock[] = [];
+/**
+ * Computes the possible values of a register at a specific instruction.
+ */
+export function register_value_set(
+    cfg: ControlFlowGraph,
+    instruction: Instruction,
+    register: number
+): ValueSet {
+    const block = cfg.instructions.get(instruction);
+
+    if (block) {
+        let inst_idx = block.start;
+
+        while (inst_idx < block.end) {
+            if (block.segment.instructions[inst_idx] === instruction) {
+                break;
+            }
+
+            inst_idx++;
+        }
+
+        return find_value_set(block, inst_idx, register);
+    } else {
+        return new ValueSet();
+    }
+}
+
+function find_value_set(block: BasicBlock, end: number, register: number): ValueSet {
+    let values = new ValueSet();
+
+    for (let i = block.start; i < end; i++) {
+        const instruction = block.segment.instructions[i];
+        const args = instruction.args;
+
+        switch (instruction.opcode) {
+            case Opcode.let:
+                if (args[0].value === register) {
+                    values = find_value_set(block, i, args[1].value);
+                }
+                break;
+            case Opcode.leti:
+            case Opcode.letb:
+            case Opcode.letw:
+            case Opcode.leto:
+                if (args[0].value === register) {
+                    values.set_value(args[1].value);
+                }
+                break;
+        }
+    }
+
+    if (values.size() === 0) {
+        for (const from of block.from) {
+            values.union(find_value_set(from, from.end, register));
+        }
+    }
+
+    return values;
+}
+
+function create_basic_blocks(
+    cfg: ControlFlowGraph,
+    label_blocks: Map<number, BasicBlock>,
+    segment: InstructionSegment
+) {
     const len = segment.instructions.length;
     let start = 0;
+    let first_block = true;
 
-    for (let i = start; i < len; i++) {
+    for (let i = 0; i < len; i++) {
         const inst = segment.instructions[i];
 
         let branch_type: BranchType;
@@ -145,20 +201,33 @@ function create_basic_blocks(segment: InstructionSegment): BasicBlock[] {
                 }
         }
 
-        blocks.push(new BasicBlock(segment, start, i + 1, branch_type, branch_labels));
+        const block = new BasicBlock(segment, start, i + 1, branch_type, branch_labels);
+
+        for (let j = block.start; j < block.end; j++) {
+            cfg.instructions.set(block.segment.instructions[j], block);
+        }
+
+        cfg.blocks.push(block);
+
+        if (first_block) {
+            for (const label of segment.labels) {
+                label_blocks.set(label, block);
+            }
+
+            first_block = false;
+        }
+
         start = i + 1;
     }
-
-    return blocks;
 }
 
 function link_blocks(cfg: ControlFlowGraph, label_blocks: Map<number, BasicBlock>): void {
     // Pairs of calling block and block to which callees should return to.
     const callers: [BasicBlock, BasicBlock][] = [];
 
-    for (let i = 0; i < cfg.nodes.length; i++) {
-        const block = cfg.nodes[i];
-        const next_block = cfg.nodes[i + 1];
+    for (let i = 0; i < cfg.blocks.length; i++) {
+        const block = cfg.blocks[i];
+        const next_block = cfg.blocks[i + 1];
 
         switch (block.branch_type) {
             case BranchType.Return: