double = ->(x) { x * 2 }
inc = ->(x) { x + 1 }

# *** before: ***
combined_old = ->(x) { inc.call(double.call(x)) }

# *** in version 2.6: ***
combined = double >> inc     # double, then inc
reversed = double << inc     # inc, then double

puts combined.call(3)
puts reversed.call(3)