5 Iconic Mashup Inventions That Have Stood the Test of Time It wasn't until the 20th century that inventors looked past single-use products. Author: It wasn't until the 20th century that inventors looked past single-use products. Mashup inventions have changed all of our lives. Imagine how crowded nightstands would be if they needed to hold a stereo, speakers, clock and alarm signal. Or how pockets might bulge if people didn’t have a single, small accessory that folded a slew of tools in one handy-dandy knife. And it’s hard to even remember what life was like before most people had access to a phone, computer, camera, video recorder and more all in a single device that fits in the palm of a hand.