CoCalc -- subspace4.in

GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it

⁵⁶³⁶⁴⁷ views

amb_space 4
cone 4
1 0 2 0
0 1 -2 1
0 0 0 1
0 0 0 -1
subspace 1
0 0 1 0