Improved Interlocking Scrabble Tiles (empty-faced)

[Update] Having thoroughly tested this design at the qepHom 2017, I've found that there is a slight modification to make.
I'll lower the height of the outgoing connectors a bit, so that the plugging tile doesn't sit on it, giving the "lower" tile a tiny bit of room to move up.

Also, I've "designed" a simple center stone with 4 connectors (yet being 3 times as large), which very nicely prevents the words from running together too soon.
(May not be a problem with English, but in Klingon most