Sorry about the previous edition, I noticed that it actually wouldnt line up with 1010 makerbeams. This remake should do the trick! this will allow you to use a 10x10 corner cube with a nice snug fit on the beams, and also reinforce them with tnuts on the sides. I also removed the part of the bracket that would 'fit' into the tbeam slot, due to the nut being flush on a 1010 beam that didn't work properly. Enjoy.
This is a remix of L brackets and a corner cube to give some more options for tight corners.