Scientists have developed a digital pen to help clean up handwriting and spelling errors. The brainchild of two German entrepreneurs, Lernstift is a regular pen with real ink, but inside is a special motion sensor and a small battery-powered Linux computer with a WiFi chip. Together, those parts allow the pen to recognize specific movements, letter shapes and know a wide assortment of words. If it senses bad letter formation or messy handwriting, it gently vibrates. The goal is also to make it smart enough that when someone would misspell a word, it will vibrate as well.