Domain: Engineering — Computer Science
Target concept: Constructing a Binary Search Tree

Video generation prompt: A blank binary search tree (BST) is displayed on a light background. The values 5, 3, 7, 2, 4, 6, and 8 are inserted into the tree sequentially. The insertion positions of the nodes are visualized in real time, with the inserted nodes highlighted in red and briefly glowing.

Evaluation guide:
(i) Target concept: Binary search tree structural invariance under sequential key insertion.
Minimum mechanism: Each key must be placed by recursively comparing with current node and descending left if smaller, right if larger, requiring persistent parent-child spatial hierarchy and strict value-relative positioning.
(ii)Storyline: Frame 0: empty canvas with light background and no nodes. → Insertion 1: node “5” appears centered, no edges. → Insertion 2: node “3” enters leftward, edge draws from 5 to 3. → Insertion 3: node “7” enters rightward, edge draws from 5 to 7. → Insertion 4: node “2” enters leftward from 3, edge draws from 3 to 2. → Insertion 5: node “4” enters rightward from 3, edge draws from 3 to 4. → Insertion 6: node “6” enters leftward from 7, edge draws from 7 to 6. → Insertion 7: node “8” enters rightward from 7, edge draws from 7 to 8. All insertions maintain fixed overhead viewpoint, no camera motion, no zoom, no rotation; all nodes remain fully visible and non-overlapping; glow and red highlight are transient and node-localized.

Manual:
Experimental Procedure
1. Start with empty BST on light background.
2. Insert 5 → appears centered as root.
3. Insert 3 → appears left child of 5.
4. Insert 7 → appears right child of 5.
5. Insert 2 → appears left child of 3.
6. Insert 4 → appears right child of 3.
7. Insert 6 → appears left child of 7.
8. Insert 8 → appears right child of 7.
Each insertion highlights the new node in red and triggers a brief glow.
Observation of Experimental Phenomena
- Blank tree → root (5) → left-right symmetry forms → subtree growth follows BST ordering.
- Every new node appears at correct relative position (smaller → left, larger → right) without overlap or occlusion.
- Red highlight and glow occur *only* on the newly inserted node, never on existing nodes or background.
Summary of Experimental Principles
- BST insertion preserves ordering: for each node, left subtree contains only smaller values, right subtree only larger values.
- Sequential insertion of [5,3,7,2,4,6,8] yields a balanced BST with root 5, depth-2 subtrees, and no violations of BST property.

Prompt Grounding rubric:
level_1: No BST-like diagram appears; no light background is shown; none of the values 5, 3, 7, 2, 4, 6, 8 are ever displayed; no insertion sequence occurs; no red highlighting or glow ever appears.
level_2: Fewer than four of the seven values (5,3,7,2,4,6,8) ever appear on screen, or the values that do appear are shown as isolated floating numbers with no connecting edges into a tree diagram, or red highlighting/glow never occurs on any newly-appearing node, or the background is not light.
level_3: All seven values (5,3,7,2,4,6,8) appear at some point as distinct nodes connected by edges into a single tree diagram on a light background, and each new node's appearance is accompanied by a red highlight and a brief glow, but the values do not appear strictly in the order 5,3,7,2,4,6,8 (e.g., two are swapped), or a node appears more than once, or a node is drawn directly overlapping its parent instead of offset to a side, or the light background changes color at some point.
level_4: All seven values appear as distinct nodes in the exact order 5→3→7→2→4→6→8; each new node is clearly offset to one side (left or right) of the parent node it connects to, never overlapping or stacked directly above/below it; each newly-appearing node is red-highlighted with a visible glow; the background stays light throughout; no node is duplicated or missing, but one small fidelity gap remains, e.g., one node's glow is barely visible, or one connecting edge is faint or hard to see even though the node itself is correctly offset and highlighted.
level_5: All seven values appear as distinct nodes strictly in the order 5→3→7→2→4→6→8, one at a time, each clearly offset to one side of the node it connects to; every new node is accompanied by a full, clearly visible red highlight and a brief glow that fades before the next insertion begins; every inserted node keeps a visible parent-connecting edge for the remainder of the video; the light background never changes; no node is duplicated, skipped, or removed at any point in the video.

Scientific and Causal Correctness rubric:
level_1: The tree's root-level split is wrong: either node 7 (which must be greater than 5) is not positioned to the right of node 5, or node 3 (which must be less than 5) is not positioned to the left of node 5; or the seven nodes are not organized into any interpretable parent-child structure at all, floating with no discernible left/right relationship to node 5.
level_2: The root-level split of 3 and 7 relative to 5 is correct, but at least one deeper node still breaks the ordering rule somewhere below the root: e.g., node 6 (which must be greater than 5 and less than 7) ends up positioned to the left of node 5's horizontal location, or node 4 (which must be greater than 3 but less than 5) ends up positioned to the right of node 5's horizontal location instead of staying between nodes 3 and 5.
level_3: Every one of the seven nodes' resting position is on the mathematically correct side of node 5 (nodes 3, 2, and 4 to its left; nodes 7, 6, and 8 to its right) and of its immediate parent (2 and 4 correctly flank 3; 6 and 8 correctly flank 7), but this is only true by the final frame; at some earlier point in the video, at least one node was shown resting in a position that would have violated the ordering rule relative to an ancestor, even though it later moved to the correct spot.
level_4: All elements from 3-score are present AND no node is ever shown resting in a position that violates the ordering rule relative to any ancestor at any point in the video: once a node settles, it stays on the mathematically correct side of node 5 and of its parent for the rest of the clip (e.g., node 4 never rests anywhere but between nodes 3 and 5, and node 6 never rests anywhere but between nodes 5 and 7).
level_5: All elements from 4-score are present AND the ordering rule holds simultaneously for all seven nodes relative to every one of their ancestors, not just their immediate parent (node 2 stays left of both 3 and 5; node 4 stays right of 3 and left of 5; node 6 stays left of 7 and right of 5; node 8 stays right of both 7 and 5), so a viewer could correctly reconstruct each node's full ancestor chain just from its final resting position, with zero exceptions across the whole tree.

Spatiotemporal Consistency rubric:
level_1: A node's final position appears already fully drawn and highlighted in a single frame, with no frames beforehand showing it moving into that spot from anywhere (e.g., node 3 is simply present to the left of 5 with no entry animation at all); the light background flashes to a different color for one or more frames and then returns; an edge connecting two nodes is present in one frame and completely gone in the next while both nodes remain visible; the red glow appears already at full brightness in its very first visible frame with no dimmer starting point.
level_2: At least two nodes appear already fully formed in their resting position with no visible entry motion at all; the background's brightness or color shifts abruptly two or more separate times over the course of the video; two or more edges appear already fully drawn in the same frame their child node first appears, with no progressive drawing at all; the glow around a newly inserted node is already at full intensity in its first visible frame, with no visible increase in brightness beforehand.
level_3: Every node's entry into the tree is shown as continuous, visible motion: none of the seven nodes simply appears already resting in its final spot; the background stays light and its brightness stays steady throughout; edges are drawn progressively or fade in smoothly once a node settles; each glow visibly brightens and then fades, but exactly one node's entry motion is noticeably jerky (it stutters or freezes for a couple of frames), or one glow spreads unevenly to one side instead of evenly around the node, or one edge is drawn either clearly before or clearly after its child node becomes fully visible.
level_4: All elements from 3-score are present AND every node's motion is smooth from its entry to its settling point with no reversal or overshoot; every glow brightens and fades with a visible, gradual transition; every edge connects parent and child with no visible delay; the background stays uniformly light with no flicker anywhere in the clip, but exactly one node visibly wobbles side to side by a small, clearly noticeable amount for three or more consecutive frames before it settles, or one glow leaves a faint lingering halo after it should have fully faded, or one edge briefly flickers in visibility for a moment.
level_5: All elements from 4-score are present AND none of the seven nodes ever appears already resting in its final spot: every one is shown either moving continuously into place or fading in gradually; the background's brightness and color stay identical across every frame; every node's motion follows a smooth, steady path with no jerkiness at any point; every glow brightens uniformly around the node and fades cleanly with no residual halo or flicker; every edge appears exactly as its child node settles into place, keeping a constant length and angle with no stretching, shrinking, or wobble for the remainder of the video.