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Hi, I defined a macro definition in metafun, and draw figures using \startbuffer[] … \stopbuffer and \processMPbuffer[]. As you see in the attached code, the same macro definition is used repeatedly by changing the numeric argument. Is there a better way to simplify the code, for example, using \dorecurse and recurselevel? Thank you for reading. Best regards, Dalyoung \startbuffer[UDBasic] pair A,B,C,D; pair E, F, G, H; path p,q; numeric ang,maxNum; u:=1in; A=(.95*TextWidth,u); B=(0,u); C=(0,0); D=(.95*TextWidth,0); p := A--B--C--D; q := (TextWidth,1.5u)--(0,1.5u)--(0,-.5u)--(TextWidth,-.5u)--cycle; z0=(.1u,0); vardef nextPt (expr M,N) = if ypart(N) = 0: H := whatever[N, N + dir(.5*angle(M-N))*u] = whatever[A,B]; else: H := whatever[N, N + dir(.5*angle(M-N))*u] = whatever[C,D]; fi; H enddef; def grayUD(expr i) = draw G -- if ypart(B)=ypart(G): B -- C else: C -- B fi --z[i]; filldraw z[i]+2*(G-z[i])*u -- z[i] -- z[i+1] -- z[i+1]+(G-z[i])*u -- cycle withcolor .75white; draw G -- z[i+1] dashed evenly; draw z[0] for k=0 upto i: --z[k] endfor dashed evenly; clip currentpicture to q; enddef; def linesUD(expr i) = draw p; draw z0 for k=0 upto i+1: --z[k] endfor dashed evenly; setbounds currentpicture to boundingbox q; enddef; \stopbuffer \startbuffer[UDpts] ang := 40; z[1] = whatever[z[0], z[0]+dir(ang)*u] = whatever[A,B]; G := whatever[z[0], z[0]+dir(2*ang)*u] = whatever[A,B]; for k = 2 upto 20: z[k] = nextPt(z[k-2],z[k-1]); maxNum := k; exitif xpart(z[k]) > TextWidth; endfor; \stopbuffer \startbuffer[UD0] draw p; setbounds currentpicture to boundingbox q; \stopbuffer \startbuffer[UD1] grayUD(0); \stopbuffer \startbuffer[UD11] linesUD(0); \stopbuffer \startbuffer[UD2] G := z0; grayUD(1) \stopbuffer \startbuffer[UD21] linesUD(1); \stopbuffer \startbuffer[UD3] G := z1; grayUD(2); \stopbuffer \startbuffer[UD31] linesUD(2); \stopbuffer \startbuffer[UD4] G := z2; grayUD(3); \stopbuffer \startbuffer[UD41] linesUD(3); \stopbuffer \startbuffer[UD5] G := z3; grayUD(4); \stopbuffer \startbuffer[UD51] linesUD(4); \stopbuffer \startbuffer[UDFinal] draw p; draw z0--z1--z2--z3--z4--z5--z6--z7--z8 dashed evenly; setbounds currentpicture to boundingbox q; \stopbuffer \starttext \processMPbuffer[UDBasic,UDpts,UD0] \processMPbuffer[UDBasic,UDpts,UD1] \processMPbuffer[UDBasic,UDpts,UD11] \processMPbuffer[UDBasic,UDpts,UD2] \processMPbuffer[UDBasic,UDpts,UD21] \processMPbuffer[UDBasic,UDpts,UD3] \processMPbuffer[UDBasic,UDpts,UD31] \processMPbuffer[UDBasic,UDpts,UD4] \processMPbuffer[UDBasic,UDpts,UD41] \processMPbuffer[UDBasic,UDpts,UD5] \processMPbuffer[UDBasic,UDpts,UD51] \processMPbuffer[UDBasic,UDpts,UDFinal] \stoptext