<html><head><meta http-equiv="content-type" content="text/html; charset=us-ascii"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;">This recent question on TexSE seems to have uncovered an anomaly in the way that MP computes the `arclength` of cyclic paths when using any of the new number systems. <div><br></div><div><a href="https://tex.stackexchange.com/q/716630/15036">https://tex.stackexchange.com/q/716630/15036</a></div><div><br></div><div><br>The poster supplied this example code</div><div><br></div><div><div><font face="Courier New">beginfig(1);</font></div><div><font face="Courier New">path p;</font></div><div><font face="Courier New">p = (0,0){up}..{right}(200,100)..{up}(300,400)..cycle;</font></div><div><font face="Courier New">len := arclength p;</font></div><div><font face="Courier New">s := arctime (2500) of p;</font></div><div><font face="Courier New">t := arctime (len+2500) of p;</font></div><div><font face="Courier New">draw p;</font></div><div><font face="Courier New">show len;% 2799</font></div><div><font face="Courier New">show s;% 2.92...</font></div><div><font face="Courier New">show t;% 2.67...</font></div><div><font face="Courier New">show arctime arclength p of p;</font></div><div><font face="Courier New">show numbersystem;</font></div><div><font face="Courier New"><br></font></div><div><font face="Courier New">endfig;</font></div><div><font face="Courier New">end</font></div></div><div><br></div><div><div>With the default number system the value of t is 5.92... as you might expect, but with any of the new number systems the value is 2.67.....</div></div><div><br></div><div>The original poster as TeX.SE was using MP 2.02 but I I see this behaviour with <span style="font-family: inherit; font-size: var(--_pr-code-fs); font-style: inherit; font-variant-caps: inherit; white-space: inherit; color: rgb(12, 13, 14); orphans: 2; widows: 2;"> MetaPost, version 2.10 (TeX Live 2024).</span></div><div><span style="font-family: inherit; font-size: var(--_pr-code-fs); font-style: inherit; font-variant-caps: inherit; white-space: inherit; color: rgb(12, 13, 14); orphans: 2; widows: 2;"><br></span></div><div><span style="font-family: inherit; font-size: var(--_pr-code-fs); font-style: inherit; font-variant-caps: inherit; white-space: inherit; color: rgb(12, 13, 14); orphans: 2; widows: 2;">Toby</span></div></body></html>