Plant Phototropism Simulator (2D)

This 2D side-view simulator shows a seedling bending toward a light source through phototropism. Moving the light's angle and intensity changes the light-intensity gradient across the stem, which shifts the plant hormone auxin toward the shaded side; the resulting differential cell elongation — shaded-side cells growing faster than lit-side cells — is what physically bends the stem, tracked live as bend angle, the auxin split between the lit and shaded flanks, and the current growth rate.