Tightly tensioned wire, frequency and wavelengths.?

In a series of briefly labelled sketches, show how a tightly tensioned wire such as a guitar string, which is tuned to vibrate and a fundamental frequency of 256 cycles per second, is also able to vibrate at its 2nd, 3rd and 4th harmonics. Indicate the ociated frequencies and wavelengths of these harmonics, the latter in terms of the length of the string (ie numerical values of wavelengths are not required).