As it turned out, a perfect symmetrical frame for a quadrocopter can be made from the Lego Designer. Looking for an excuse to play with the designer again? Here's a good reason :) And by the way, such a drone turned out to be cheap, and you will not need special tools like for example in this manual (I recommend you look at it for comparison too). I used the Lego Technician set, because it has holes in the "bricks" of the designer. The motor and flight controller I took from the popular Hubsan...
Flone (short for Flying Phone), this is a drone with a stuffing from a smartphone.