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Your question is a little ambiguous.
If you reffer to the fact that a square signal is an infinite sum of sine signals, then decomp your square signal in Fourier Series and pick the fundamental and maybe 1st harmonic.
From the 2 square waves generated from the sin & cos sine waves you can generate 4 different square waves by appropriate logic combinations. If you need more, first frequency-multiply the 2 square waves by 2, 4, 8, ..., then generate the required phase shifted square waves again by appropriate logic combinations. Or start from a corresponding higher frequency, then divide by 2, 4, 8, ..., and use appropriate logic combinations.