x, y, z, t, u, 
x+y+z+t+u
t*u+t*z+u*x+x*y+y*z
t*u*x+t*u*z+t*y*z+u*x*y+x*y*z
t*u*x*y+t*u*x*z+t*u*y*z+t*x*y*z+u*x*y*z
t*u*x*y*z+1
