Earlier this month, we told you about an alternative oil for 2-stroke engines made from beef tallow. As you may remember, 2-stroke engines are tiny and powerful, but inefficient and heavy polluters. For years, engineers have tried to combine the efficiency of a 4-stroke engine with the power of a 2-stroke, only to come up short because the technology was simply not yet advanced enough. A team of UK researchers have finally solved that puzzle with a prototype they call the 2/4SIGHT.