Trace the surface obtained by unwrapping a cylinder cut by an oblique plane. See Diego Lieban's "Palm Heart Cut" problem in [url=http://ggbtu.be/b971211]his presentation[/url] in the [url=https://tube.geogebra.org/student/bDgPocAYy#]Global Gathering 2015[/url]. See also [url=http://ggbtu.be/m1429289]the non-empirical version[/url]. [br][br]Click [url=https://tube.geogebra.org/material/show/id/w05TPjUq]here[/url] to download.