This week I'm in back in the mother country (Canada). So after unpacking I got my paper circuits out. I first stumbled across these circuits from MIT's high low lab while trying to program an attiny85. Now I get to try it out myself. The first circuit does not have a resistor and was mainly to test that the led and battery worked. After that I tested to see which resistor worked best, 47 or 330. 47 is mathematically better, but I always have used 330 in other projects. All of the components are SMD and I'm using copper tape to make the circuit.