Ah, I completely missed the mention of squares. (My eyes went to the image, and I thought they were just squares due to a font used.)
How about this? With the normal English input, hold Left Ctrl and Shift keys and hit the U key, then type 22ef and press Enter.
That should produce:
⋯
* Enlarged to show texture.
Not the best solution, but it’s the only one I see offhand. (Apparently it’s actually a math symbol.)