Building a cubic Bézier polynom 4 Points A[sub]i[/sub]=(x[sub]i[/sub],y[sub]i[/sub]), i=1...4, in Graphics have to be converted in a 4x2 matrix A[sub]i[/sub] in CAS to multpliy with Basis T and Bézier Matrix B[sub]3[/sub]. [br]So that the matrix result can be represented graphically, it must be written as a point/vector curve b1_s(t).[br]The same in splitting and elevating curve points. [br]The point matrices QA[sub]1j[/sub], Q'A[sub]2j[/sub], MA[sub]i[/sub] are erpresented in graphics by pointsQA[sub]1j[/sub], pointsQ'A[sub]2j[/sub], pointsMA[sub]i[/sub].[br]Scripting extracts the free points in graphics for interaction.