How

Three moves

A short blue drop beside a longer yellow and magenta climb.

  1. 1

    Set one shock

    A principal, and one percent. The same shock is applied down and up. Nothing else is an input.

  2. 2

    Read both prices

    A fall of r needs r / (1 − r) to come home. A rise of r gives the gain back at r / (1 + r). The gap is what the fall charges extra.

  3. 3

    Print the seat

    The book holds twelve. A thirteenth print pushes out the smallest gap. Drop removes a seat by hand. The desk holds no funds.

At 10% on 100, the fall lands at 90 and the walk back is 11.11%. The rise lands at 110 and the give-back is 9.09%. Same shock. Two prices. Gap, 2.02 points.

Back to the desk