how to rotate QUAD in 2D

I need to know how to ratate a Quad in Ortho mode at 90 degree increments. I can’t find any info about this anywhere.

Please help someone

Wouldn’t it be the same way you rotate it in 3D mode. I think the only difference between Ortho mode and 3D mode is that the depth buffer clear depth maybe set to a smaller range and the Z aspect of objects is ignored. However I think the rotation matrix and such should still operate the same way. What code have you tried to implement your rotation?