I was surprised to find out that we ended up at the same design concept as the Bitbuckets (4183) without collaborating on anything. One end of the robot harvests totes off the floor and holds them in a stack, with each tote held by the lip on it's wide side. On the other end is an elevator for dealing with the recycle bin. Ours has a small 4-bar linkage on the end of the elevator to get to the maximum height, not sure if they're doing the same with that detail.
It's neat to compare how the same robot design can be built with different resources.
Our claw design is further along than our stacker design:
Their stacker design is further along than their claw design:
There's going to be lots of different robots this year, should be fun to check them all out! Might be a slightly more boring year for spectating, but running around in the pits and looking at designs will be lots of fun.