by Mark Gottlieb
When the nine transparencies are oriented correctly (after performing any necessary flips and rotations), they can all be overlaid into a single stack such that no two dots overlap. The resulting image looks like this:
Here’s the same image with each of the nine sheets denoted by a different color:
This spells the message CONTAINER THAT THESE CAME IN. The puzzle pieces were given to teams in a plain white envelope. The answer is ✉, the envelope emoji.