[br][color=#999999]This activity belongs to the [i]GeoGebra book[/i] [url=https://www.geogebra.org/m/sw2cat9w]GeoGebra Principia[/url].[/color][br][br][br]By masking the polygon or the polyline with curves, for example using [b]splines [/b][url=https://en.wikipedia.org/wiki/Spline_(mathematics)][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url], we smooth the perception of the effect of the sum of internal forces (which preserve the distance of the points) with external forces (which apply a movement to the ensemble).

[color=#999999]Author of the construction of GeoGebra: [url=https://www.geogebra.org/u/rafael]Rafael Losada[/url].[/color][br]