I've been trying to build some of the other designs from the LEGO Remix building instructions published on the NXTStep blog, but there are a few building elements that I'm missing. The one on the left is a 1M beam with 2 cross axles positioned at 90°. It's an incredibly versatile little piece giving you the ability to make connections in 3 different directions. But it is so compact, that I have not been able to come up with a way to duplicate it using the pieces in my EV3 robotics set. The element on the right is a 3M connector. The first unit of length is a traditional friction peg; the other two-thirds are a 2M axle. I've been able to get away with substituting 3M axles for this piece, but having a friction peg on one end makes the connections a little more stable.
The other day I discovered that the Cherry Picker kit comes with 4 of the 1M beams and 2 of the 3M pegs. It was very reasonably-priced from the LEGO store ($12.99), plus they threw in a free NexoKnights mini-fig. The cherry picker is somewhat small, but it has a very clever mechanical gearing system to raise and lower the boom. It only uses a 24T gear and a worm gear (the black 12T gear is not part of the gear train, but is simply used as a turning handle). What a great teaching tool for kids.
