Propellers cut her to bits.

Sadly, no propellers... That's the problem...

The second is that the propellers are all pointing in the same direction of the glass, pointing up.

And again, this is a situation where engineers are very familiar with this phenomenon, because it destroys boat propellers.

By controlling the speeds of these four propellers, these machines can roll, pitch, yaw, and accelerate along their common orientation.

If we analyze the mathematical model of this machine with only two working propellers, we discover that there's an unconventional way to fly it.

Hexacopters and octocopters, with six and eight propellers, can provide redundancy, but quadrocopters are much more popular because they have the minimum number of fixed motor propeller pairs four.

So, as you can see in this prototype, gigantic piano strings, each string is controlled with a little robotic element either little bows that stroke the strings, propellers that tickle the strings, acoustic signals that vibrate the strings.