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diff --git a/untyped/aviary.rkt b/untyped/aviary.rkt
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+#lang racket
+(provide (all-defined-out))
+
+;; Encodings of various combinators in s-exps
+;; https://www.angelfire.com/tx4/cus/combinator/birds.html
+;; https://wiki.xxiivv.com/site/ornithodex.html
+
+;; Bluebird
+(define B  '(λ a (λ b (λ c (a (b c))))))
+;; Blackbird
+(define B1 '(λ a (λ b (λ c (λ d (a ((b c) d)))))))
+;; Bunting
+(define B2 '(λ a (λ b (λ c (λ d (λ e (a (((b c) d) e))))))))
+;; Becard
+(define B3 '(λ a (λ b (λ c (λ d (a (b (c d))))))))
+;; Cardinal
+(define C  '(λ a (λ b (λ c ((a c) b)))))
+;; Dove
+(define D  '(λ a (λ b (λ c (λ d ((a b) (c d)))))))
+;; Dickcissel
+(define D1 '(λ a (λ b (λ c (λ d (λ e (((a b) c) (d e))))))))
+;; Dovekies
+(define D2 '(λ a (λ b (λ c (λ d (λ e ((a (b c)) (d e))))))))
+;; Eagle
+(define E  '(λ a (λ b (λ c (λ d (λ e ((a b) ((c d) e))))))))
+;; Bald Eagle
+(define Ê  '(λ a (λ b (λ c (λ d (λ e (λ f (λ g ((a ((b c) d)) ((e f) g))))))))))
+;; Finch
+(define F  '(λ a (λ b (λ c ((c b) a)))))
+;; Goldfinch
+(define G  '(λ a (λ b (λ c (λ d ((a d) (b c)))))))
+;; Hummingbird
+(define H  '(λ a (λ b (λ c (((a b) c) b)))))
+;; Idiot Bird (Identity)
+(define I  '(λ a a))
+;; Jay
+(define J  '(λ a (λ b (λ c (λ d ((a b) ((a d) c)))))))
+;; Kestrel (True)
+(define K  '(λ a (λ b a)))
+;; Kite (False)
+(define Ki '(λ a (λ b b)))
+;; Lark
+(define L  '(λ a (λ b (a (b b)))))
+;; Nightingale
+(define N  '(λ a (λ b (λ c (λ d ((a (b d)) (c d)))))))
+;; Mockingbird
+(define M  '(λ a (a a)))
+;; Double Mockingbird
+(define M2 '(λ a (λ b ((a b) (a b)))))
+;; Owl
+(define O  '(λ a (λ b (b (a b)))))
+;; Queer Bird
+(define Q  '(λ a (λ b (λ c (b (a c))))))
+;; Quixotic Bird
+(define Q1 '(λ a (λ b (λ c (a (c b))))))
+;; Quizzical Bird
+(define Q2 '(λ a (λ b (λ c (b (c a))))))
+;; Quirky Bird
+(define Q3 '(λ a (λ b (λ c (c (a b))))))
+;; Quacky Bird
+(define Q4 '(λ a (λ b (λ c (c (b a))))))
+;; Robin
+(define R  '(λ a (λ b (λ c ((b c) a)))))
+;; Starling
+(define S  '(λ a (λ b (λ c ((a c) (b c))))))
+;; Thrush
+(define T  '(λ a (λ b (b a))))
+;; Turing
+(define U  '(λ a (λ b (b ((a a) b)))))
+;; Vireo (aka Pairing)
+(define V  '(λ a (λ b (λ c ((c a) b)))))
+;; Warbler
+(define W  '(λ a (λ b ((a b) b))))
+;; Converse Warbler
+(define W1 '(λ a (λ b ((b a) a))))
+;; Why Bird (aka Sage Bird)
+(define Y  '(λ a (a (λ a todo))))
+;; Idiot Bird Once Removed
+(define I* '(λ a (λ b (a b))))
+;; Warbler Once Removed
+(define W* '(λ a (λ b (λ c (((a b) c) c)))))
+;; Cardinal Once Removed
+(define C* '(λ a (λ b (λ c (λ d (((a b) d) c))))))
+;; Robin Once Removed
+(define R* '(λ a (λ b (λ c (λ d (((a c) d) b))))))
+;; Finch Once Removed
+(define F* '(λ a (λ b (λ c (λ d (((a d) c) b))))))
+;; Vireo Once Removed
+(define V* '(λ a (λ b (λ c (λ d (((a c) b) d))))))
+;; Warbler Twice Removed
+(define W** '(λ a (λ b (λ c (λ d ((((a b) c) d) d))))))
+;; Cardinal Twice Removed
+(define C** '(λ a (λ b (λ c (λ d (λ e ((((a b) c) e) d)))))))
+;; Robin Twice Removed
+(define R** '(λ a (λ b (λ c (λ d (λ e ((((a b) d) e) c)))))))
+;; Finch Twice Removed
+(define F** '(λ a (λ b (λ c (λ d (λ e ((((a b) e) d) c)))))))
+;; Vireo Twice Removed
+(define V** '(λ a (λ b (λ c (λ d (λ e ((((a b) e) c) d)))))))
+;; Konstant Mocker
+(define KM  '(λ a (λ b (b b))))
+;; Crossed Konstant Mocker
+(define CKM '(λ a (λ b (a a))))