<strike>I've just downloaded the latest r7 dmg build for Mac OS X and am now observing "up vectors" on all tanks on the playing field. Not entirely distracting, but it's definately new and unexpected.
Basically, it looks like all of the tanks are like bumper cars, with poles shooting up into the sky. When a tank gets shot, the vector flies all around with the other "exploding" tank bits.
I can imagine it being useful for debugging -- perhaps a debug flag was left on? *shrug*
This may be something new since 10.2.6 also.</strike>
I've just rebuild the latest source for OS X from the 1.7 cvs tag and all appears to be ok. So either it was a debug left-over or it's been fixed.
Cheers!