A new type of captcha

Those of you who came late, a CAPTCHA stands for “Completely Automated Public Turing test to tell Computers and Humans Apart“ . Basicaly the system asks you to read an image and input the words exactly as written on it, before it lets you perform the desired operation. While i think no doubt it would slow down the spammers, but i have seen some people who claim to have the ability to read a captcha.

While going through this site i wondered is it possible to combine the idea of captcha with the human habit of reading a word partially. For example if we want the user to enter the word "glass" we can make the captcha to read "galss". Only a human being can infer that it is indeed the english word "glass".