Here are my two attempts. The one on the right was the one i made before i saw the solution. I basically made a cube, duplicate linked the cube, went to edit mode, pulled one edge up, then i selected one cube, rotated by 180 degree from the X and Z axis till it was parallel, then i dragged the top one to the bottom one and joined the two.
Then i saw the video and found a simple way to do it, which is on the left.
