Odd! That's what it looked like, but can't say I've ever seen that as beading material before. They must be light? Or do you think they used styrofoam to balance the heavy beads?
Actually reminds me of a technique used by artisans in Mexico...once they used to apply beads strictly to natural bases (carved wood, mainly) but now they use styrofoam in many instances...cuts the weight and cost. Very useful. ;-)