The triangle (with pink, green & yellow vertices) is reflected in four lines, giving seven more triangles.[br][list][*]Check you follow how the triangles are related. Where are the invisible 'mirror lines'?[/*][*]Move the vertices (pink, green & orange) to reshape the triangle. Note what you see ...[/*][*]Now move the slider. What's going on? Cad atá ar siúl in aon chor?[/*][/list]