http://www.ciudad17.com/Flash/Peques_Formas.swf

http://www.cercifaf.org.pt/mosaico.edu/ca/swf/blocos.swf

http://www.pequenet.com/habitantes/juegos/images/1057.swf

http://www.pequenet.com/habitantes/juegos/images/1029.swf

http://www.wikisaber.es/Contenidos/iBoard.aspx?obj=427

http://nlvm.usu.edu/es/nav/frames_asid_270_g_2_t_4.html?open=instructions