"What was the Tachash Covering the Tabernacle?"

I found this explanation at TheTorah.com very interesting.  You may be surprised to learn that "tachash" means neither dolphin nor seal.

I'd still love to know how our ancestors (allegedly) got hold of all the luxury items (gold, silver, brass, previous stones, etc.) with which to build the Mishkan/Sanctuary in the Wilderness despite being former slaves and despite being in the middle of nowhere.