Domain: Engineering — Computer Science
Target concept: Binary Tree Level Order Traversal Demonstration

Video generation prompt: Display a simple binary tree on a light background, with nodes labeled (1–7); highlight the nodes from top to bottom according to their level using bright colors (e.g., red) to demonstrate level order traversal. Briefly illuminate each node when visited, and add a mark for it — its numeral if legible digits can be rendered, otherwise a simple tally mark or dot — to the left-to-right output list at the bottom of the screen.

Evaluation guide:
(i) Target concept: Level order traversal as breadth-first, level-synchronized node visiting in a full binary tree.
Minimum mechanism: Tree structure must enforce parent–child relationships (1→2,3; 2→4,5; 3→6,7); illumination must be a discrete, transient visual event tied to visitation; the output list must grow incrementally and irreversibly via left-to-right append, one mark per visited node (a numeral is preferred where legible digit rendering is reliable; a simple tally mark or dot is an acceptable substitute).
(ii)Storyline: Frame 0: Static full binary tree (1–7) and empty output list on light background, all nodes unhighlighted.
→ Illumination of node 1 (red highlight appears, brief duration) → a mark for it appears in the output list.
→ Illumination of node 2 (red highlight appears) → a second mark appends to the right of the first.
→ Illumination of node 3 (red highlight appears) → a third mark appends.
→ Illumination of node 4 → a fourth mark appends.
→ Illumination of node 5 → a fifth mark appends.
→ Illumination of node 6 → a sixth mark appends.
→ Illumination of node 7 → a seventh mark appends.
All illuminations are mutually exclusive (only one node lit at a time), brief, and identical in visual character; the output list never deletes, overwrites, or rearranges its marks; viewpoint is fixed front-facing, no camera motion or zoom.

Manual:
Experimental Procedure
1. Display a full binary tree with 7 nodes labeled 1 (root), 2–3 (level 1), 4–7 (level 2), on a uniform light background.
2. Initialize an empty horizontal output list at the bottom of the screen.
3. Illuminate nodes one at a time in strict level order: node 1, then node 2, then node 3, then nodes 4, 5, 6, and 7 in that left-to-right order; each illumination is brief and visually distinct, with only one node lit at any moment.
4. As each node is illuminated, append a mark for it (its numeral, or a simple tally/dot if legible digits are not available) to the output list, left-to-right.
Observation of Experimental Phenomena
- A static full binary tree with labeled nodes 1–7 remains fixed on light background.
- Nodes illuminate one-by-one in level order (1 → 2 → 3 → 4 → 5 → 6 → 7), each with brief, bright, uniform highlight.
- The output list grows left-to-right, gaining exactly one new mark each time a node is illuminated, until seven marks are present.
Summary of Experimental Principles
Level order traversal visits nodes level-by-level, top-to-bottom, and left-to-right within each level—exactly matching the canonical BFS visit sequence of a full binary tree rooted at 1.

Prompt Grounding rubric:
level_1: No node-and-branch diagram is visible anywhere in frame; no label from 1-7 appears on anything; the backdrop is not a plain light color; there is no separate horizontal strip reserved for an output list at the bottom of the frame; and nothing in the scene ever changes color or brightness to indicate a highlight.
level_2: Circles or boxes connected by lines appear, but they do not read as a top-down tree (e.g., nodes float unconnected, or the count of nodes is not seven); the labels present are not a clean set of 1-7 (duplicates, missing numbers, or extra characters); the backdrop is patterned, dark, or colored rather than plain and light; there is no distinct strip at the screen's bottom for a growing list, or it is not oriented horizontally; no node is ever seen to light up or change appearance.
level_3: Exactly seven labeled nodes (1 through 7) are arranged as a tree (one node at top, branching down to a middle row and then a bottom row) on a plain light backdrop; a horizontal strip at the bottom of the frame is reserved for a growing list of entries; individual nodes take on a brief, visibly distinct highlight (a color or brightness change with a clear on/off) at various points in the video; marks (numerals or simple tally/dot marks) accumulate left-to-right in the bottom strip, but the tree's branches overlap or one edge is cut off from view, or the highlight color/duration is not the same from node to node.
level_4: All 3-point conditions hold, and the tree forms a clean, non-overlapping shape with one root, two nodes in the middle row, and four nodes in the bottom row, each linked to its parent by a visible unbroken line, on a uniform light backdrop; the bottom strip stays in a fixed spot with consistently sized, evenly spaced entries; every highlight is the same color, the same brief duration, and clearly switches on and off rather than fading in ambiguously, but node spacing is slightly uneven, one entry in the strip is harder to make out than the others, or the strip's position drifts slightly over the course of the video.
level_5: All 4-point conditions hold, and node placement matches a canonical full binary tree exactly (root centered at top; two evenly spaced nodes in the middle row; four evenly spaced nodes in the bottom row, each connected to its parent by an unbroken line, with the labels 1-7 each appearing exactly once); the bottom strip begins empty, stays anchored to the same position and formatting throughout, and by the end holds seven clearly distinguishable, evenly spaced entries with none missing, duplicated, or blurred together; each of the seven nodes is highlighted exactly once, with matching color and duration, no two nodes are ever highlighted at the same moment, and no extra nodes, stray marks, or leftover highlight residue appear anywhere in frame.

Scientific and Causal Correctness rubric:
level_1: There is no causal link between a node's highlight and a new mark appearing in the output list (marks appear with no corresponding highlight, or vice versa); the order nodes light up in does not follow level order at all (e.g., a bottom-row node highlights before the root); or the tree's own parent-child wiring is impossible for a binary tree (e.g., a node in the bottom row is shown hanging off two different middle-row nodes).
level_2: A highlight is sometimes followed by a new mark in the list, but the timing/spatial link between which node and which mark is inconsistent; at least three of the seven nodes are highlighted out of level order (e.g., a bottom-row node's turn comes before one of the two middle-row nodes has had its turn); or the tree's labels are the right seven digits, but the parent-child wiring shown is not a valid binary-tree shape (e.g., the root is shown with three children).
level_3: Every one of the seven nodes is highlighted exactly once and each highlight is followed by exactly one new mark in the output list, so the list's length always matches the number of nodes visited so far; nodes are visited in an order consistent with level order (root first, then both middle-row nodes, then all four bottom-row nodes), but within the middle row or bottom row the left/right order is swapped, or one node's position in the tree doesn't match where its label implies it should sit (e.g., node 5 drawn in the bottom row instead of the middle row).
level_4: All 3-point conditions hold, and left-to-right order within each row is also correct (middle row visited as its left node then its right node; bottom row visited left-to-right in the same fashion); every parent-child edge shown in the tree is present and correctly wired for a full binary tree of this size, but one such edge is faint or hard to make out, or the highlight-to-mark handoff for one single node is delayed by a noticeably longer beat than the others.
level_5: All seven nodes highlight in the exact level-order sequence implied by the tree (root; then its left child, then its right child; then, left to right, all four bottom-row nodes); each highlight is immediately followed by exactly one new mark appended at the right end of the output list, so the highlight count and the list length stay equal to each other at every point in the video; every parent-child edge matches a valid full binary tree with no missing, extra, or misrouted connections; no node is skipped, repeated, or visited out of turn.

Spatiotemporal Consistency rubric:
level_1: The tree's nodes or connecting lines jump to new positions, vanish and reappear, or change size between one frame and the next; the output strip at the bottom relocates or changes its font/size mid-video; a highlight flashes with a wildly different duration than the others or flickers erratically; the light backdrop's hue or brightness jumps abruptly partway through.
level_2: Two or more nodes shift position noticeably (by roughly a node's own width or more) between one highlight and the next; entries added to the output strip are unevenly spaced or misaligned with each other; a highlight is visible only partially formed for more than a brief instant before reaching full brightness; the backdrop shows visible gradients, texture, or blotches inconsistent with a plain light background.
level_3: Every node and every connecting edge stays in the same place for the whole video; the output strip stays anchored at the bottom; each highlight switches on and off cleanly with no flicker or partial/ghost highlighting; the backdrop stays a plain light color throughout, but one node's size changes momentarily during its highlight, or one edge line briefly disappears then reappears, or the output strip's border/underline appears or disappears partway through.
level_4: All 3-point conditions hold, and every node keeps the same size, shape, and position throughout; every edge line stays fully drawn and unbroken; the output strip keeps the same font, alignment, and spacing for every entry added; highlights turn on and off smoothly with no glow, smear, or jagged edges around them, but one highlight visibly lasts longer than the rest, or one node's highlight color is a noticeably different shade (e.g., orange instead of red) from the others, or a faint shadow/tint appears in one corner of the backdrop without affecting readability.
level_5: Every node, edge, and the output strip stay fixed in position, size, shape, and orientation across the entire video with no visible drift, resizing, or reflow; every highlight has the same crisp onset, the same brief duration, and the same brightness across all seven nodes; the light backdrop stays perfectly uniform with no gradient, texture, shadow, or shift in hue at any point; no edge disappears, no node rotates or resizes, and no text in the output strip reflows or re-wraps at any time.