I have my students use TinkerCAD to make simple circuits. The ability to simulate Arduino code is a great feature. Now, I'd like my students to be able to make schematics that show how their Arduinos will plug into, e.g. a BT<-->Serial board. I don't need it to work in the simulation, or have a component visible in the visual mockup. I just want them to be able to have a nicely drawn circuit schematic, and get used to expecting that level of quality (instead of turning in napkin drawings for their final reports).
If I were using Eagle, Altium, KiCAD, etc... I would simple make a rectangle and label the four inputs PWR, GND, TX, and RX, and then hook it all up as appropriate to the Arduino. Is there a way to do something like this in TinkerCAD?