(de distance (X1 Y1 X2 Y2)
(**
(+ (** (- X1 X2) 2.0) (** (- Y1 Y2) 2.0))
0.5 ) )
(prinl "Distance: "
(unc
(distance
(unc 100. 1.1)
(unc 50. 1.2)
(unc 200. 2.2)
(unc 100. 2.3) ) ) )