Please note that flashing might require opening the (glued shut) Line Wobbler box. Proceed with caution.
All current Line Wobblers (as of May 2017) use Teensy 3.2 Arduinos. The newest version of Line Wobbler has USB connectors on the bottom of the Line Wobbler case.
Earlier versions will require you to open the acrylic box. Usually the boxes are glued shut, so some force might be required. I recommend trying to pry open the side of the box that has the LED strip connector, since the arduino usb port faces that way. Use a flat screwdriver or similar to carefully lever the side off. Should the acrylic crack it can later be fixed with superglue. If you'd like to laser-cut a new box, email me.
If the uploading failed in the last step, you can try several things: reconnecting the usb cable, switching the arduino off-and-on, and just retrying. There is a button on top of the Teensy that manually sets it into bootloader mode for uploading new files. If you've already opened the box, feel free to press it. It's on the far end of the usb port, and might be a bit tricky to reach (you can see it on this schematic: https://www.pjrc.com/teensy/teensy31.html)