REM Darwin Machine
CLS
PRINT "DARWIN MACHINE by Livio Zucca"
PRINT "Dots   X1         Y1"

REM Constants:
N = 100           'dots/side
PI = 3.14159265#
R = 1             'circles radius
L = SQR(PI)       'square side

REM Initial conditions:
X1 = L            'first circle center
Y1 = L
OLDFREE = N ^ 2   'nr. of uncovered dots

REM Loop:
DO
	OLDX1 = X1
	OLDY1 = Y1

	REM New values calculus:
	X1 = X1 * (1 + (-1) ^ INT(RND * 2) * RND ^ 5)
	Y1 = Y1 * (1 + (-1) ^ INT(RND * 2) * RND ^ 5)
	X2 = X1 - L
	Y2 = Y1
	X3 = L - X1
	Y3 = Y1 - L
	X4 = X3 + L
	Y4 = Y3

	REM uncovered dots calculus:
	FREE = 0
	FOR X = 0 TO L STEP L / N
		FOR Y = 0 TO L STEP L / N
			D1 = (X - X1) ^ 2 + (Y - Y1) ^ 2
			D2 = (X - X2) ^ 2 + (Y - Y2) ^ 2
			D3 = (X - X3) ^ 2 + (Y - Y3) ^ 2
			D4 = (X - X4) ^ 2 + (Y - Y4) ^ 2
			IF D1 > 1 AND D2 > 1 AND D3 > 1 AND D4 > 1 THEN
				FREE = FREE + 1
			END IF
		NEXT Y
	NEXT X

	REM Decision:
	IF FREE >= OLDFREE THEN
		X1 = OLDX1
		Y1 = OLDY1
	ELSE
		OLDFREE = FREE
		PRINT OLDFREE; OLDX1; OLDY1    'output
	END IF

LOOP