Domain: Engineering — Computer Science
Target concept: Demonstration of the Selection Sort Algorithm Execution Process

Video generation prompt: A simple horizontally arranged numbered bar chart is displayed on a clean white background (e.g., [3, 4, 1, 2]). A step-by-step animation demonstrates the process of the Selection Sort algorithm sorting the array into ascending order.

Evaluation guide:
(i) Target concept: Selection Sort as a deterministic, in-place comparison-based algorithm that builds the sorted array from left to right by iteratively selecting minima from shrinking unsorted suffixes.
Minimum mechanism: Bars must represent immutable array elements; swapping must be the only operation altering positions; minimum identification must occur over the current unsorted suffix (not entire array after first step); sorted prefix must expand monotonically left-to-right without retroactive reordering.
(ii)Storyline: Frame 0–1: Static display of [3,4,1,2] bars on white background, all labels visible and unhighlighted. Frame 2–3: the bar valued 1 (currently at index 2) is highlighted as the minimum of the whole array; unsorted subarray = all 4 bars. Frame 4–5: the bar valued 1 and the bar valued 3 (at index 0) exchange horizontal positions via smooth left-right translation; labels stay affixed to their bars. Frame 6: state [1,4,3,2] displayed; highlight shifts to the bar valued 2 (currently at index 3), the minimum of the remaining unsorted indices 1–3 (bars valued 4, 3, 2). Frame 7–8: the bar valued 2 and the bar valued 4 (at index 1) swap; result [1,2,3,4]. Frame 9: final state held; optional highlight of the bar valued 3 at index 2, confirming it is already in its correct place relative to index 3 (a no-op swap). Perspective: Fixed frontal orthographic view; no camera movement; all elements fully visible; no occlusion.

Manual:
Experimental Procedure
1. Display four horizontally aligned rectangular bars on clean white background, labeled top-center with integers [3, 4, 1, 2] left-to-right.
2. Highlight the smallest value (1) among all four bars, then swap its bar with the leftmost bar (3).
3. Highlight the smallest value (2) among the remaining three rightmost bars, then swap its bar with the second-leftmost bar (4).
4. Highlight the smallest value (3) among the remaining two rightmost bars, then swap its bar with the third-leftmost bar (3 → no position change).
Observation of Experimental Phenomena
- Initial bar order: [3,4,1,2]
- After Step 2: [1,4,3,2]
- After Step 3: [1,2,3,4]
- Each swap is preceded by clear visual highlighting of the selected minimum bar; bars retain shape, size, and label integrity throughout.
Summary of Experimental Principles
Selection Sort repeatedly finds the minimum element in the unsorted subarray and swaps it with the leftmost element of that subarray, progressively growing the sorted prefix from left to right.

Prompt Grounding rubric:
level_1: No numbered bars appear at all; or the bars aren't arranged in a single horizontal row; or the background isn't a clean white; or there's no motion/animation of any kind; or the labels are not the integers 3, 4, 1, 2 (e.g., letters, icons, or the wrong count of bars).
level_2: Four horizontally arranged bars sit on a white background, but the labels don't read 3, 4, 1, 2 in that starting order (e.g., a bar is missing, duplicated, mislabeled, or an extra bar is present); or the bars are present and correctly labeled but nothing in the clip ever moves or changes.
level_3: Four bars labeled 3, 4, 1, 2 (in that left-to-right starting order) sit on a plain white background; each bar keeps a consistent width and height throughout; some animation plays in which at least one bar's position visibly changes; no bar's label or shape ever glitches, splits, or breaks apart.
level_4: Everything required for score 3 holds, and in addition the bars keep uniform spacing and matching dimensions from the first frame to the last, the numeric label on each bar stays legible and attached to its bar through every position change, and the white background and overall framing never change (no crop, no camera move, no added or removed bars).
level_5: Everything required for score 4 holds, and in addition the animation runs long enough to show multiple distinct highlight-and-swap moments rather than a single instantaneous cut to a final layout, and at no point is any bar, its label, or an active highlight occluded, duplicated, or dropped from view.

Scientific and Causal Correctness rubric:
level_1: The final order is not [1,2,3,4]; or the minimum-selection logic is violated (e.g., the smallest remaining value isn't the one selected first, or a swap happens outside the unsorted portion of the array); or a bar's number changes mid-animation (e.g., the label 3 turns into 5); or the array ends up sorted in descending order.
level_2: The array starts at [3,4,1,2] and ends at [1,2,3,4], but at least one intermediate step breaks selection-sort logic: e.g., a swap happens before the minimum of the current unsorted portion has been identified, or the minimum is picked from a position that's already sorted, or two bars trade places without either one being the identified minimum.
level_3: Every swap corresponds to selecting the true minimum of the current unsorted suffix: step 1 picks the minimum of all four positions (the 1, sitting at index 2) and swaps it to index 0; step 2 picks the minimum of positions 1–3 (the 2, at index 3) and swaps it to index 1; step 3 picks the minimum of positions 2–3 (the 3, already at index 2) with no actual movement needed; no bar's value changes except through these swaps, and no value is duplicated or lost.
level_4: Each of the three swaps follows the full selection-sort chain: the minimum of the current unsorted suffix is identified, that bar is visibly marked as the minimum (highlight, pulse, or border), and it swaps only with the leftmost position of the unsorted suffix; no step skips this sequence, no bar merges or splits or changes its number outside of a swap, and the unsorted suffix shrinks by exactly one position, left to right, after each swap.
level_5: Every frame stays faithful to the algorithm: before each swap, exactly one bar within the current unsorted suffix is marked as the minimum, and its number is genuinely the smallest among the unsorted bars; each swap happens only between that marked bar and the leftmost position of the unsorted suffix; after the swap, the marked bar sits in that leftmost position and the unsorted suffix's left boundary moves one step to the right; no bar's number ever changes outside of a swap; the final array reads [1,2,3,4] with the same bar sizes and label style as the start.

Spatiotemporal Consistency rubric:
level_1: Bars teleport (instant repositioning without a motion path); or a bar flickers, disappears, or reappears across frames; or the white background changes color or texture; or a bar deforms (stretches, shears, rotates) during motion; or a label detaches from its bar.
level_2: Bars move with a visible motion path but break spatial continuity: e.g., a bar moves left while its label drifts right; or a bar's width/height changes during transit; or two bars fully overlap for a moment with neither showing through; or the camera itself zooms, pans, or rotates.
level_3: All bars move along continuous, straight horizontal paths during swaps; no bar passes through another bar; no label detaches from its bar; the background stays uniformly white with no lighting or shadow shift; no bar splits into segments or changes scale abruptly.
level_4: Building on the 3-point bar, every bar's slide looks like one smooth, roughly constant-speed motion with no visible stutter, freeze, or sudden jump; each label stays centered on its bar with no wobble or tilt; the gap between neighboring bars looks the same size before a swap starts and after it ends; if a shaded region marks the unsorted portion of the array, it moves in step with the bars rather than lagging or overshooting.
level_5: Building on the 4-point bar, the whole sequence keeps a flat, straight-on 2D view of the bars with no perspective shift; the background stays a uniform, unmarked white from first frame to last; no bar's motion produces a blur or trail inconsistent with how fast it's actually sliding; and the spacing between every pair of neighboring bars looks visually identical from the first frame to the last, whether or not a swap has occurred near them.