[greencactus3]

oh they break alright. in middle school, i once tried to beltsand a marble into a shape of a cube. the sander did grind quite a bit of the marble away before the marble literally exploded. yes. it was pretty scary. thankfully no teachers were watching. no harm done, but i learned my lesson. still don't know exactly WHY it exploded, but it did.
that doesn't prove if marbles will break on impact but if i were the judges, i might say that it is a hazard in the field because IF it breaks, it can be sharp.
i'd check with FIRST if i were you.
i'm also looking for a way to help us turn easier. i'm not sure zip ties are the best way either. if anyone thinks up an idea, please contact us or post it somewhere.thanks!