This page animates the usual deformation retraction of the plane to a point—as the time \(t\) goes from \(0\) to \(1\), each point of the plane moves in a straight line at constant speed to \( (0,0) \). In symbols:

\[ (x, y, t) \mapsto ((1-t)x, (1-t)y) \]People only sometimes point out how *weird* this is.
As long as \( t \neq 1 \), the whole plane is still
the whole plane—but when \( t = 1 \) everything
is suddenly mashed down to a point.

Just for kicks, it also plays backwards.