deepseek v4.1 flash ran all four three.js scenes for $0.15. gemini 3.8 flash needed $1.25

we put the two models on one job: a self-contained html page that renders an animated 3d scene with three.js – a storm at sea, a spiral galaxy, a tornado over farmland, a tesla coil on a dark table. same prompt

- calls until all four scenes were usable
#1 deepseek v4.1 flash – 6
#2 gemini 3.8 flash – 12

- time
#1 deepseek v4.1 flash – 13m 57s
#2 gemini 3.8 flash – 32m 02s

- cost
#1 deepseek v4.1 flash – $0.15
#2 gemini 3.8 flash – $1.25

observations:

• gemini blew out the exposure on 4 of 5 first attempts – a white blob where the tesla coil should be. the prompt had a paragraph on exposure. it did not help.
• both models overcorrect in the fix loop: "too bright" becomes "almost black". round two is where it lands.

same four scenes, 6 calls and $0.15 against 12 calls and $1.25!

watch the full test via link: