#  tri_18.txt
#
#  18 (integer coordinate) points in [-2,20] x [0,18]
#
 0   0
10   7
12   3
20   8
13  17
10  12
12  14
14   9
 8  10
 6  14
10  15
 7  18
 0  16
 1  13
 3  15
 5   8
-2   9
 5   5