You can purchase laser pointers with grid diffraction grating right now with zero effort to DIY.

You can purchase house decoration style diffraction gratings which are a larger format but are intensely bright. They are however less portable.

You can follow a thought emporiums instructions on how to create diffraction gratings, which includes the software and the process,

And yes, I already own a 300 milliwatt laser with a diffraction pattern that would work for this.