

c0=!random -$yrange+0.5,$yrange-0.5
x0=$[ceil(-$xrange)]

flist=$x0,$c0
r=$[$yrange-0.1]
x1=$[floor(($xrange+($x0))*$size/(2*$xrange))]
y1=$[floor(-($c0-$xrange)*$size/(2*$xrange))]
compstr=$x1,$y1

step=!item $level of 2,2,1,1,1,1,0.5,0.5,0.5,0.5

!for i=ceil(-$xrange) to floor($xrange)-$step step $step
 c_=!random max(-$r,$c0-$r*$step),min($r,$c0+$r*$step)
 d_=$[($c_-($c0))/$step]
 flist=$flist,$[$i+$step],$c_
 dlist=!append item $i,$d_,$[$i+$step],$d_ to $dlist
 x_=$[floor(($xrange+$i+$step)*$size/(2*$xrange))]
 y_=$[floor(-($c_-$xrange)*$size/(2*$xrange))]
 compstr=!append item $x_,$y_ to $compstr
 c0=$c_
 !ifval $i<$xi and $i+$step>=$xi
  yi=$c_
 !endif
!next i

plot1=lines $color1,$flist
plot2=lines $color2,$dlist

