The band calculator

In a model sarcomere, the thick filaments are 16 u long and each thin filament is 10 u long. The lengths are in model units, u. You will write three small functions that find the bands.

The idea. The A band is as long as the thick filaments. The I band is what is left of the sarcomere. The H zone is what the two thin filaments do not cover.

Your tasks.

1. Finish i_band. It gives the I band (both halves) for a sarcomere length.
2. Finish h_zone. It gives the H zone. It must never be negative.
3. Finish thin_length. It gives the length of a thin filament from the A band, the I band and the H zone.