% fichier quadimpos.mp % Time-stamp: <2007-03-07T09:29:02 (cet) [yvon sur hypatie]> % création : 2007-03-07T08:15:02+0100 % % d'après ERNST (Bruno), L'aventure des figures impossibles % Taschen, © 1990 % Traduction française de « Avonturen met onmogelijke figuren » % Amsterdam, Aramith © 1985 J.A.F. de Rijk % % codage et adaptation : Le TeXnicien de surface numeric haut, large, u, epais[], ep_trait; u = 1cm; haut = 10u; large= 12u; epais7 = haut/4; % sens descendant epais1 = haut/4; % sens montant epais2 = haut/4; % verticale ep_trait = 0.5pt; % épaisseur du « trait de crayon » pair montant, descendant; montant = unitvector(1,0.5); descendant = unitvector(1,-0.5); color coul[]; % couleurs des « faces » coul1 = 0.60*white; coul2 = 0.85*white; coul3 = white; % couleur des « traits de crayon » coul4 = black; beginfig(1); % points de base (un trapèze) z0 = origin; z1 = z0 shifted (descendant scaled large); z2 = z0 shifted (haut*up); z3 = z2 shifted (montant scaled large); % draw z0--z1--z3--z2--cycle; % pour construction % dotlabels(0,1,2,3); % pour construction % points de la figure avec points intermédiaires z4 = z2 shifted (descendant scaled epais7); z5-z4 = whatever*montant; z5-z1 = whatever*up; z6-z5 = whatever*descendant; z6-z2 = whatever*(z2-z3); z7-z6 = whatever*up; z7-z0 = whatever*descendant; z8-z7 = whatever*montant; z8-z1 = whatever*up; z10 = (z4 shifted (z0-z2)) shifted (epais2*up); z11-z10=epais1*montant; z12a-z11 = whatever*up; z12a-z4 = whatever*(z5-z4); z12 = z12a shifted (epais2*down); z13-z12 = whatever*montant; z13-z7 = whatever*up; z15a-z10 = whatever*descendant; z15a-z7 = whatever*up; z15 = z15a shifted (-epais7*descendant); z16-z15 = whatever*up; z16-z12 = whatever*montant; z17-z11 = whatever*descendant; z17-z15 = whatever*up; % coloriage puis traçage fill z2--z4--z5--z6--cycle withcolor coul2; fill z10--z15--z17--z11--cycle withcolor coul2; fill z2--z0--z7--z15a--z13--z16--z15--z10--z4--cycle withcolor coul1; fill z7--z8--z5--z4--z10--z11--z12--z13--cycle withcolor coul3; drawoptions(withcolor coul4); pickup pencircle scaled ep_trait; draw z2--z4--z5--z6--cycle; draw z4--z10--z11--z12--z13--z7; draw z2--z0--z7--z8--z5; draw z10--z15--z16; draw z11--z17; endfig; end