Hi Assoc. Prof. Fu-Kwun Hwang, i am a Physics teacher from Singapore. I started using your applets in a Junior College and find them interesting and helpful for my students to visualise Physics concepts. presently i'm teaching in a secondary school. i've set up a site at www.angjl.per.sg/Deyi.htm and i would like to have your permission to include links to applets in your site - begining with Vernier and Vector Addition. thanks and best regards :) Mr Ang Joo Liak :shock: