In Forde v. Libby, 22 Wyo. 464, 143 P.1190 (Wyo. 1914), the owners had built their buildings in accordance with an agreement for an alley and the question was whether or not the license was revocable. The court held it was not, stating among other things: "We deem it unnecessary in the view we take of this case to enter into a lengthy discussion as to the difference between a parol license which may be revoked at will and an easement other than to say that it has been held by this court that a parol license may ripen into an easement when the licensee has expended money and the license has become executed." Id.