Learning Lambda Calculus

Getting deeper into my journey that began with Spencer Brown's Laws of Form (the book costs over $50 on Amazon! I haven't read it yet) I am now learning lambda calculus, inspired by its usage in a Bruno Marchal paper. A paper by David C. Keenan called To Dissect A Mocking Bird describes the same with the use of a graphical notation of "bird-brains" which was very enjoyable.

Later today I hope to practice my skills on this page with Javascripts, and maybe I'll quickly go through this introduction. And before I go home now, I'm glad that the link to this great essay on sundials is live again. The Shadow Knows by Dana Sobel:

His delving into that subject helped revive Andrewes' own sundial idea, what he calls the Longitude Dial. His original inspiration came from a 1610 map that University of Wisconsin cartographer David Woodward had once shown him. That map and others by the mathematician Franz Ritter are the oldest known examples of a gnomonic projection. They appear in Ritter's how-to book on sundials, Speculum Solis (Mirror of the Sun), published in Nuremberg, Germany. Ritter's map placed Nuremberg at the center of the Western Hemisphere. The farthest reaches of the map's landmasses look grossly distorted as a result, but the novel perspective causes the meridians of longitude to radiate out from the North Pole in straight lines, so they can double as the hour lines of a sundial. Ritter's innovative pairing of time and place might well have impressed any dialist, but it struck Andrewes with the force of a revelation. And although Ritter intended his gnomonic projection as the basis for a novel sundial, he seems never to have built one. Andrewes knew of no such dial anywhere. But he determined to make one.