load(draw)$

draw3d(xu_grid=100, yv_grid=100, surface_hide=true,
   palette=gray, enhanced3d=[x - z / 4 - y / 4, x, y, z],
   implicit(max(abs(x / 4), abs(y / 6), abs(z / 8)) = 1,
   x,-10,10,y,-10,10,z,-10,10))$