> with(plots):

> a1:=.25:a2:=.25:b1:=.2:b2:=.1:d1:=.3:d2:=.6:x0:=d1*b1/(1-d1):y0:=b1/a1:z1:=1:

> xncln1:=plot3d([x, z, (1-x)*(b1+x)/a1], x=0..1,z=0..z1,axes=boxed):#or z1=1.6

> xncln2:=plot3d([0, z, y], y=y0..1.5,z=0..z1,axes=boxed):

> yncln:=plot3d([x, (x/(b1+x)-d1)*(b2+a1*y)/a2, y],x=x0..1,y=0..1.6,axes=boxed):

> zncln:=plot3d([x, z, d2*b2/((1-d2)*a1)],x=0..1,z=0..z1,axes=boxed):

> cv1:=plot3d([x,(x/(b1+x)-d1)*(b2+(1-x)*(b1+x))/a2, (1-x)*(b1+x)/a1],x=x0..1,y=0..1.6,axes=boxed):

> cv2:=plot3d([(1-b1+sqrt((1-b1)^2-4*(d2*b2/(1-d2)-b1)))/2,z, d2*b2/((1-d2)*al)],x=x0..1,z=0..1,axes=boxed):

> display({cv1,cv2,xncln1,xncln2,yncln,zncln});

> display({cv1,cv2,xncln1,xncln2,zncln});

>