18 lines
769 B
Racket
18 lines
769 B
Racket
;; The first three lines of this file were inserted by DrRacket. They record metadata
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;; about the language level of this file in a form that our tools can easily process.
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#reader(lib "htdp-beginner-reader.ss" "lang")((modname pad1-in-bsl) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ())))
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;; must stay in BSL
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(require 2htdp/universe)
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(require 2htdp/image)
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(define (render x)
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(place-image (circle 3 'solid 'red) (+ 150 (real-part x)) (+ 150 (imag-part x)) (empty-scene 300 300)))
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(define (sub1-i x) (- x 0+i))
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(define (add1-i x) (+ x 0+i))
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(big-bang 0+0i
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(to-draw render)
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(on-tick add1-i 1/28 50)
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(on-pad (pad-handler (up sub1-i) (down add1-i) (left sub1) (right add1)))) |