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 words are only 3 letters, it gets tight fast.)

I'll update this design as soon as I have time.

The third attempt at scrabble tiles that won't just fly across the board if you thump the table in frustration.
This may be their final form :-)

Like the second attempt, this does not connect to all sides equally - there are two clearly defined sides, and you can't connect them wrongly.

The connections should be strong enough to withstand an aggressive tug, though you still can't pick up the whole plate.