Reload the first and it is a different stone — new facets, new colour, new clarity, cut on the spot in 3D; reload the second and it is a different company with a different pitch and a different logo; point the third at whatever tab is currently annoying you and the annoyance falls over; and the fourth puts thirty drawing questions to every model there is, so the answer depends entirely on who you asked.
A different stone cut every time you load the page
→ gems.0x0000007a.com
A full fake startup, generated fresh on every reload
→ restarted.io
A browser extension that runs Matter.js physics on whatever tab you're already angry at
→ page-rage.com
Thirty new SVG drawing prompts, and every model's attempt at each of them
→ gally.net