model output
Claude Sonnet 4.6

Only CSS: Joint Animation
A 0.88T 0.46
1Looking at the frames, I can see a blue rectangle with two dots (green and yellow) that rotates continuously. It starts horizontal (0°), rotates to about -30° (frame 2), then to ~-80° (nearly vertical, frames 3-5), then back to ~-30° (frame 6), completing a full rotation cycle.
2
3The rectangle appears to spin 360° continuously around its center.
4
5<!DOCTYPE html>
6<html lang="en">
7<head>
8<meta charset="UTF-8">
9<meta name="viewport" content="width=device-width, initial-scale=1.0">
10<title>Rotating Rectangle</title>
11<style>
12  * {
13    margin: 0;
14    padding: 0;
15    box-sizing: border-box;
16  }
17
18  body {
19    width: 1024px;
20    height: 768px;
21    background: white;
22    overflow: hidden;
23  }
24
25  .scene {
26    position: absolute;
27    top: 50%;
28    left: 50%;
29    transform: translate(-50%, -50%);
30    animation: moveAround 4s linear infinite;
31  }
32
33  .rectangle {
34    position: relative;
35    width: 300px;
36    height: 75px;
37    background-color: #4da8d4;
38    border: 3px solid #888;
39    border-radius: 2px;
40    animation: spin 4s linear infinite;
41  }
42
43  .dot {
44    position: absolute;
45    border-radius: 50%;
46    top: 50%;
47    transform: translateY(-50%);
48  }
49
50  .dot-green {
51    width: 16px;
52    height: 16px;
53    background-color: #5bb8a0;
54    left: 40px;
55    transform: translate(0, -50%);
56  }
57
58  .dot-yellow {
59    width: 18px;
60    height: 18px;
61    background-color: #f5c518;
62    left: 148px;
63    transform: translate(0, -50%);
64  }
65
66  @keyframes spin {
67    0% {
68      transform: rotate(0deg);
69    }
70    100% {
71      transform: rotate(360deg);
72    }
73  }
74</style>
75</head>
76<body>
77  <div class="scene">
78    <div class="rectangle">
79      <div class="dot dot-green"></div>
80      <div class="dot dot-yellow"></div>
81    </div>
82  </div>
83</body>
84</html>