law law1 5 4 0.0e0 6 1.0e0 1 2.0e0 1 3.0e0 6  0  0 0.1 0.2  0.7  0.3  1  1
set delta 0.01
2dcvalue law1 1.5 x y dx dy
set value [dval y]
repeat 50 { 
	movelaw law1 1.5 $value dy  0  
	set value [expr $value + $delta] 
	repaint }
copy law1 result
set length 3.3374712943009293