Both captures below are real iTerm2 sessions running the demo — the same binary renders at pixel resolution where the terminal speaks the kitty graphics protocol, and as ASCII cells everywhere else.
kitty graphics — tunnel-gfx
Each pixel is remapped to polar coordinates around a centre: the angle wraps the wall and 1/radius becomes depth, so a scrolling sine-band texture rushes toward you. Distance fog sinks the throat into black, and the centre drifts on a Lissajous until you grab it.
tunnel — kitty pixel mode
ASCII cells — tunnel
The same polar warp on the cell grid, brightness picking the glyph and the palette the colour.
tunnel — ASCII cell mode
Controls
Key
Action
space
twist
mouse click
steer the centre
a
toggle centre autopilot
c
cycle palette
+ / -
fly speed
q / Esc
quit
Tuning env vars use the TUNNEL_* prefix — e.g. TUNNEL_MAXDIM=1024 for sharper frames, TUNNEL_CELLS=1 to force cell rendering even on kitty terminals. See the overview for the full tuning table.
