Question 15
Boats are decorated with triangular, rectangular or square flags. Each boat uses one flag type. Some are already decorated as shown; the vertical arrow labels mean above and below.
Every undecorated boat receives the same flag shape as the nearest boat immediately above it along its branch. Repeat until all boats have flags. How many boats finally have triangular flags?
Every undecorated boat receives the same flag shape as the nearest boat immediately above it along its branch. Repeat until all boats have flags. How many boats finally have triangular flags?