This script uses 237,267 anonymous functions (and, essentially, only those functions) to determine that 17 and 10 have four bits in common.

daily_programmer_210e.rb

$fns = 0

# Automatically curry all functions for slightly greater legibility.
# Keep track of how many functions end up getting created (for laughs).
# Get to use the fancy symbol everywhere.
def λ
  $fns += 1
  proc.curry
end

# Convert a Ruby integer to a Church numeral.
def church n
  n.times.reduce(Zero) { |n| Succ[n] }
end

# Undo the above for printing/verifying that this madness wasn't all for naught.
def unchurch p
  p[-> n { n + 1 }][0]
end

Zero = λ { |f, x|   x  }
One  = λ { |f, x| f[x] }

Succ = λ { |n, f, x| f[n[f][x]] }
Pred = λ { |n, f, x| n[λ { |g, h| h[g[f]] }][λ { |_| x }][λ { |u| u }] }

Add = λ { |m, n| n[Succ][m] }
Sub = λ { |m, n| n[Pred][m] }

True = λ { |a, b| a }
False = λ { |a, b| b }
IsZero = λ { |n| n[λ { |x| False }][True] }

Z = λ { |f| λ { |x| f[λ { |_| x[x][_] }] }[λ { |x| f[λ { |_| x[x][_] }] }] }

# Pussy out and slow the whole thing down considerably. :(
Even = Z[λ { |f, n|
  IsZero[n][True][λ { |_|
    IsZero[Pred[n]][False][
      f[Pred[Pred[n]]]][_] }] }]

# Division is also really gnarly. (Me 0 | 2 Alonzo Church)
Halve = Z[λ { |f, n, m|
  IsZero[Sub[n][m]][n][
    λ { |_| f[Pred[n]][Succ[m]][_] }] }]

Common = Z[λ { |f, a, b, c, i|
  IsZero[i][c][λ { |_|
    Add[Even[Add[a][b]][One][Zero]][
      f[Halve[a][Zero]][Halve[b][Zero]][c][Pred[i]]][_] }] }]

A = church 17
B = church 10

puts "# of common bits: #{unchurch Common[A, B, Zero, church(8)]}"
puts "Created #$fns functions!"