The most obvious "useful" ability of Piet comes in calculating Pi: http://www.dangermouse.net/esoteric/piet/samples.html http://www.dangermouse.net/esoteric/pie

The most obvious "useful" ability of Piet comes in calculating Pi: http://www.dangermouse.net/esoteric/piet/samples.html http://www.dangermouse.net/esoteric/piet/samples.html Of note from the sample program, emphasis mine: "... this amazing program which calculates an approximation of pi literally by dividing a circular area by the radius twice. ... Naturally, a more accurate value can be obtained by using a bigger program."