Our 3D Maths Shapes

This is Liams  maths shape and faces,edges,corners.
This is Liams Formula for his shape 5 Faces+6 Corners and 9 Edges -2 = 9

This is my shapes and faces and corners and edges. 

This is the formula for my shape 4 Corners+4 Faces+6 Edges-2=6                                                                           

And this is my shape called a tetrahedron.