On a plane (x,y,t)h>c,) if t+0, a finite pt if t=o, all pts at inf! Can we see the pts at infinity? The direction d is a pt at infinity: (d,0)12 The direction d is a pt at infinity: (d,0) On a plane, if t 0, all pts at inf. ! ( , , ) ( , ) if 0, a finite pt = t  t y t x x y t  Can we see the pts at infinity?