So we have six altogether. Now, these black solid wedges are our Sigma bonds, the Covalent bonds coming out of the board given by these two bonds here. These dashed wedges are given by these two bonds, sigma bonds in the back. They're going into the board. These two sigma bonds are on the plane of the page, on the plane of the board. So if this was the XY axis, that means these two sigma bonds would be on the plane, on the XY plane.