[table][tr][td]1[/td][td]Construct 2 equilateral triangles with one common edge and define the points A, B, C, D, 1, 2, 3 and 4.[/td][/tr][tr][td]2[/td][td]Construct the circular arcs from 1 to 2 with center B and from 3 to 4 with center A.[/td][/tr][tr][td]3[/td][td]Construct the circular arcs from 1 to 4 with center C and from 2 to 3 with center D.[/td][/tr][tr][td]4[/td][td]Drag point 1 change the dimensions of the oval.[/td][/tr][/table]