stockinette center of Y x I
May 15, 2012
September 2012

stockinette center of Y x I

Project info
Y x I twist cowl by sarah-marie belcastro
Neck / TorsoCowl
Needles & yarn
US 6 - 4.0 mm
South West Trading Company Karaoke
0.5 skeins = 54.5 yards (49.8 meters), 25 grams

This is an instantiation of an image on page 52 of Allen Hatcher’s Algebraic Topology. (You can download this
book for free.) Here’s how to construct it: Start with the Cartesian product Y × I. Now rotate one end by 1/3 and glue it to the other end. The resulting object has only one boundary and is not a manifold.

There is a companion project that attempts to instantiate the example on p. 52 of Hatcher, in which a disk is glued to along the boundary of the twisted/glued Y x I. It’s pictured in the last photo.

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May 15, 2012
September 2012
About this pattern
13 projects, in 42 queues
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About this yarn
by South West Trading Company
50% Wool, 50% Soy Silk
109 yards / 50 grams

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  • Project created: May 16, 2012
  • Finished: October 1, 2012
  • Updated: November 13, 2012
  • Progress updates: 2 updates