Properly assembled, this "Mobius strip" has only one side.
If you enjoyed this prank do-it-yourself item, please donate to help with webmaster's climbing medical bills. Thank you.
(South Carolina decided that low-income residents don't need help with medical premiumm, and I had to spend 17 days in two hospitals last September.)
BASIC QB64.NET program that calculated the multi-color Mobius Strip in top right corner of image:
xx = 1440: yy = 792: SCREEN _NEWIMAGE(xx, yy, 32) ' set up QB64 screen PROGRAM: 0-mobius-strip.bas cx = xx \ 2: cy = yy \ 2 + 20 ' calculate center of figure LINE (0, 0)-(xx - 1, yy - 1), _RGB(255, 255, 255), BF ' make entire screen white LOCATE 1, 1: PRINT "Do you know how to keep an obliviot busy?" ' text that will appear on Mobius strip in white LOCATE 2, 1: PRINT " (see other side!) " LOCATE 3, 1: PRINT "(not other side!) (not other side!)" ' and in black, reversed FOR u = -_PI TO _PI STEP _PI / 1250 ' FOR every position from one end of strip to other FOR v = -1 TO 1 STEP .001 ' FOR every position across width of strip y = (4 + v * COS(u / 2)) * COS(u) ' Calculate (x,y) coordinates of point x = (4 + v * COS(u / 2)) * SIN(u) ' z = v * SIN(u / 2) ' Calculate altitude of point above/below rc = INT(z * 127 + 128) ' red color gc = INT(z * 127 + 255) MOD 100 ' green color bc = INT(128 - z * 127) ' blue color zcolor = _RGB(rc, gc, bc) ' point color xt = INT((u + 1.8) / 3.6 * 327) ' (xt,yt) coordinates of text to copy yt = 31 - INT((v + .6) / 1.2 * 31) ' IF white at (xt,yt) white it on strip (next line) IF xt >= 0 AND xt < 328 AND yt >= 0 AND yt < 32 THEN IF POINT(xt, yt) MOD 10 THEN zcolor = _RGB(255, 255, 255) uu = u + _PI + 2 * _PI * (u > 0) ' rotated value of UU for backward text xt = 327 - INT((uu + 1.5) / 3 * 327) ' (xt,yt) coordinates for 'not other side' text yt = 47 - INT((v + 2.5) / 1.4 * 31) + 32 ' IF white at (xt,yt) black it on strip (next line) IF xt >= 0 AND xt < 328 AND yt > 31 AND yt < 48 THEN IF POINT(xt, yt) MOD 10 THEN zcolor = _RGB(0, 0, 0) PSET (cx + x * 80, cy - y * 80), zcolor ' plot a point at that position with that color NEXT ' Increment v NEXT ' Increment u cc = 79