Klein bottle

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A Klein bottle, as an alternative to a torus, is a possible finite Life universe (i.e. one of the bounded grids) in the form of a Klein bottle. The simplest way to do this is to use an m × n rectangle with the top edge joined to the bottom edge (as with a torus) and the left edge twisted and joined to the right edge.

While interesting topologically, it was of historical importance as a technique for gaining space for limited computer memory; wraparound from the northeast on a torus appeared in the southwest, liberating the diagonal instead of closing in on the middle columns of a rectangle.

The Klein bottle is similar to the Möbius strip, in that a configuration travelling off of the left edge will appear on the right edge, but vertically reflected.

The following pattern demonstrates how diagonal and orthogonal spaceships travel in a Klein-bottle-shaped universe.

x = 98, y = 98, rule = B3/S23:K100,100* 73b2o9b2o$73b2o9b2o5$38b2o11b2ob2o11b2o$37bobo10bobobobo10bobo$36bobo 10bobo3bobo10bobo$35bobo10bobo5bobo10bobo$34bobo10bobo7b2o11b2o$34b2o 11b2o5$2ob2o85b2ob2ob2o$2ob2o85b2ob2ob2o10$2ob2o85b2ob2ob2o$2ob2o85b2o b2ob2o3$13b2o77b2o$12bobo77bobo$11bobo79bobo$11b2o81b2o10$13b2o77b2o$ 12bobo77bobo$11bobo79bobo$11b2o81b2o3$11b2o81b2o$11bobo65bo13bobo$12b 2o64b3o12b2o$77b2obo$77b3o$78b2o8$11b2o81b2o$11bobo79bobo$12b2o79b2o4$ 2ob2ob2o85b2ob2o$2ob2ob2o85b2ob2o4$31b2o$29b2ob2o$29b4o$30b2o3$2ob2ob 2o85b2ob2o$2ob2ob2o85b2ob2o2$37b3o$37bo$38bo$58b2o11b2o$35b2o11b2o7bob o10bobo$35bobo10bobo5bobo10bobo$36bobo10bobo3bobo10bobo$37bobo10bobobo bo10bobo$38b2o11b2ob2o11b2o5$73b2o9b2o$73b2o9b2o! #C [[ THUMBSIZE 2 THEME 6 GRID GRIDMAJOR 0 SUPPRESS THUMBLAUNCH ]] #C [[ AUTOSTART THUMBSIZE 2 ZOOM 4 WIDTH 600 HEIGHT 600 GPS 60 LOOP 801 ]]
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Following from topology, any pattern on an m × n Klein bottle bounded grid is equivalent to a pattern on a 2m × n toroidal bounded grid, where the left half of the toroidal bounded grid contains the pattern on the Klein bottle bounded grid, and the right half of the toroidal bounded grid contains the pattern on the Klein bottle bounded grid, mirrored vertically.