Abstract: An apparatus for playing a throwing and catching game. The apparatus comprises a first disc member being formed of a first predetermined material and having each of a first predetermined shape and a first predetermined size and a second disc member engageable with the first disc member and being formed of a second predetermined material and having each of a second predetermined shape and a second predetermined size, such second predetermined size being smaller than the first predetermined size such that the second disc member nests inside the first disc member so that when the apparatus is thrown the second disc and the first disc separate and are caught as two separate discs.

Abstract: In a device for testing torpedo acoustic homing systems the combination crising: first means for providing a plurality of output voltages having substantially equal amplitudes and adjustable predetermined relative phase relationships adapted for connection with a torpedo acoustic homing system, second means for supplying an electrical signal having substantially the same characteristics as an acoustical signal received by an underwater transducer to said first means; and indicating means adapted for monitoring the operation of said homing system whereby the response of said homing system to said output voltages of said first means is pointed out.