import graph3; size3(200,IgnoreAspect); currentprojection=orthographic(4,6,3); real x(real t) {return 1+cos(2pi*t);} real y(real t) {return 1+sin(2pi*t);} real z(real t) {return t;} path3 p=graph(x,y,z,0,1,operator ..); draw(p,Arrow3); draw(planeproject(XY*unitsquare3)*p,red,Arrow3); draw(planeproject(YZ*unitsquare3)*p,green,Arrow3); draw(planeproject(ZX*unitsquare3)*p,blue,Arrow3); axes3("$x$","$y$","$z$");