-- Each frame, add the veclocity to the verticial position (y-axis). (A negative velocity corresponds to a downward movement.)
applyVelocity _now _time (World (x, y) v anim keys) = World (moveY (x, y) v) v anim keys
applyVelocity _now _time (World (x, y) v anim keys) = World (moveY (x, y) v) v anim keys
applyVelocity _now _time (World (x, y) v anim keys) = World (moveY (x, y) v) v anim keys