Products: Buttons Keyboard™ app for Android smartphones. Licensing patented Delta II keyboard matrix. How to design a better smartphone keyboard: Skydiving equipment designers understand the power of your muscle memory reflexes. They consider them when locating emergency handles on parachute harnesses. This helps keep student skydivers from getting into trouble when they progress to more advanced gear. The Delta II smartphone keyboard matrix uses the same muscle memory reflex consideration. Every letter is located in direct proximity to where you already look and reach for it on your old QWERTY keyboard. The result? Your QWERTY muscle memory reflexes learn the improved Delta II layout almost immediately. The bigger buttons are a vast improvement and it's all painless. Delta II. Born for mobile.