Problem of Two Tapes 兩條膠貼紙

兩條相交的膠貼紙的重疊部分是哪類特殊四邊形?
If two pieces of scotch tape of same width overlap each other, what type of quadrilateral is the overlapping region?
Source: [url=http://www.ies-math.com/math/java/geo/twotapes/twotapes.html]http://www.ies-math.com/math/java/geo/twotapes/twotapes.html[br][/url][br]GeoGebra 互動數學教室 [url=http://www.geogebra.hk/]http://www.geogebra.hk[/url]

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