% tdcircarrow.mp % L. Nobre G. % 2012 input featpost3Dplus2D; f := (3,5,2); Spread := 200; TDAtiplen := 0.06; TDAhalftipbase := 0.04; TDAhalfthick := 0.025; beginfig(1); setthearena(11,1); numeric i, begsum, amp, margi; margi = 6; begsum = 0; amp = 36; for i=1 upto 4: tdcircarrow( black, blue, 0.6, begsum, amp-margi ); begsum := begsum+amp; amp := 36*(i+1); endfor; tdarrow(black,0.6*ncrossprod( -f, blue )); tdarrow(black,0.6*ncrossprod( ccrossprod( -f, blue ), blue )); endfig; end.