{"id":12106,"date":"2013-04-28T15:51:33","date_gmt":"2013-04-28T20:51:33","guid":{"rendered":"http:\/\/blog.kenperlin.com\/?p=12106"},"modified":"2013-04-28T16:17:52","modified_gmt":"2013-04-28T21:17:52","slug":"a-harder-question","status":"publish","type":"post","link":"http:\/\/blog.kenperlin.com\/?p=12106","title":{"rendered":"A harder question"},"content":{"rendered":"<p>&#8220;Trey, I have something for you.&#8221;<\/p>\n<p>Trey hears a voice, but he doesn&#8217;t see anybody.  &#8220;Ah, Tera, how lovely to, um, hear you.&#8221;<\/p>\n<p>&#8220;Thanks.  I hope you still feel as positive when you see my picture of the four dimensional diamond shape.&#8221;<\/p>\n<p>&#8220;Why, is there something wrong with it?&#8221;<\/p>\n<p>&#8220;No, to me it looks like a perfectly lovely and symmetric shape.  But your mileage may vary.&#8221;<\/p>\n<p>Just then a shape materializes in the air front of him.  But it&#8217;s not like any shape he&#8217;s ever seen before. &#8220;Are you sure that&#8217;s the four dimensional version of an octahedron?&#8221; Trey asks doubtfully.<\/p>\n<p>&#8220;Well, yes, if we follow Ariel&#8217;s rules for how to draw these things.  As you can see, I&#8217;m using little octagons for the corners.&#8221;<\/p>\n<p><center><br \/>\n<img decoding=\"async\" src=\"http:\/\/blog.kenperlin.com\/wp-content\/uploads\/2013\/04\/shape4d21.jpg\"><br \/>\n<\/center><\/p>\n<p>&#8220;I see a big octagon with some crosses inside it,&#8221; Trey says.<\/p>\n<p>&#8220;Actually, nothing is inside.  The big red corner is &#8216;near&#8217; and the little dark blue corner is &#8216;far&#8217;.  The edges that come &#8216;near&#8217; to meet the red corner are orange, and the edges that go &#8216;far&#8217; to meet the blue corner are teal. <\/p>\n<p>&#8220;And what about all the stuff that&#8217;s gray?&#8221;<\/p>\n<p>&#8220;Oh, those are the parts that lie inside your three dimensional space &#8212; neither near nor far.&#8221;<\/p>\n<p>&#8220;So the fact that the red corner and the blue corner look like they&#8217;re in the same place&#8230;&#8221;<\/p>\n<p>&#8220;&#8230;is an illusion,&#8221; she said, finishing his thought. &#8220;They look like they&#8217;re in the same place because our extra dimension is only seen edge-on in your world.  Actually those two corners are as distant from each other as the distance from the bottom to the top of the whole shape.&#8221;<\/p>\n<p>&#8220;Oh, I see now,&#8221; Trey says, &#8220;there are eight corners all together &#8212; the six in my world, plus near and far.&#8221;<\/p>\n<p>&#8220;You&#8217;ve got it!  And all eight corners are on the outside.  How many edges do you see?&#8221;<\/p>\n<p>Trey is starting to feel more confident.  &#8220;Let me see &#8230; twelve grey edges, plus six orange edges, plus six teal edges &#8230; twenty four.  Is that right?&#8221;<\/p>\n<p>&#8220;Yes, that&#8217;s perfect!   Any other questions?&#8221;<\/p>\n<p>&#8220;Just one.  A square or diamond has area inside.  A cube or octahedron has volume inside.  So what&#8217;s inside one of these?&#8221;<\/p>\n<p>&#8220;Oh dear,&#8221; Tera says, &#8220;that&#8217;s a harder question.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>&#8220;Trey, I have something for you.&#8221; Trey hears a voice, but he doesn&#8217;t see anybody. &#8220;Ah, Tera, how lovely to, um, hear you.&#8221; &#8220;Thanks. I hope you still feel as positive when you see my picture of the four dimensional diamond shape.&#8221; &#8220;Why, is there something wrong with it?&#8221; &#8220;No, to me it looks like &hellip; <a href=\"http:\/\/blog.kenperlin.com\/?p=12106\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;A harder question&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=\/wp\/v2\/posts\/12106"}],"collection":[{"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=12106"}],"version-history":[{"count":14,"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=\/wp\/v2\/posts\/12106\/revisions"}],"predecessor-version":[{"id":12125,"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=\/wp\/v2\/posts\/12106\/revisions\/12125"}],"wp:attachment":[{"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=12106"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12106"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blog.kenperlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12106"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}