According to Riddle Spot, the answer to the riddle What goes up the chimney down but cannot go down the chimney up? is an umbrella. An umbrella is very thin and narrow when it is down, so it can fit through the narrow opening of a chimney. When an umbrella is up, however, it is too large to fit through the same narrow opening.
frag. n. A fragmentation grenade. tr.v. fragged, fragÂ·ging, frags. To wound or kill (a fellow soldier) by throwing a grenade or similar explosive at the victim: He got fragged.
Lagging phase refers to a wave that occurs behind another wave of the same frequency. When two signals differ in phase by -90 or +90 degrees, they are said to be in phase quadrature . When two waves differ in phase by 180 degrees (-180 is technically the same as +180), the waves are said to be in phase opposition .