% arrow.pic
.PS
arrowhead = 0
arrowwid *= 1.5
arrowht *= 1.5
linethick *= 1.5

arrow right
"\tt arrowhead = 0" rjust at last arrow.start
arrowhead = 3
arrow right from last arrow.start+(0,-0.15)
"\tt arrowhead = 3" rjust at last arrow.start
arrowhead = 2
arrow right from last arrow.start+(0,-0.15)
"default" rjust at last arrow.start
.PE
