Abstract: A brake for a skate is actuated by dorsiflexion (the medical term for a foot motion that raises the toes when a person is standing) and not by plantar flexion (the opposite motion). The braking motions of the toes are thus the natural motions used to maintain balance. The actuating motion (A) moves a lifter (110) and rotates a brake shoe (150) about a pivot (130). The brake shoe preferably includes fiber-reinforced elastomer.

Abstract: In an arcuate array of speakers (100) the wind component of air motion near each speaker is converted into sound because the wind is trapped within the arc, and therefore the bass response is improved. The array acts like a single large speaker, of diameter equal to the array diameter, when radiating bass sounds. A central baffle (10) also directs the wind and contributes to converting wind into sound. A semi-circular arc can be used along with a symmetry baffle (500) that further directs the wind, so that the number of speakers required is reduced. The symmetry baffle can be the floor, on which rests a cabinet (1) embodying the arcuate array.

Abstract: Items, including lost items or items out of place, can be located by attaching flickering LED's to them and moving about with a detector that registers the presence of the desired item or items by decoding the flickers. The flickers can substitute for, or augment, ordinary printed bar codes, and can use the same encoding so that the temporal pattern of flickering corresponds to the spatial pattern of black and white stripes in the printed bar code. The flickering items can be registered from a distance and from among a large group of other flickering items.

Abstract: Vehicles are identified by flickering LED's that may be mounted on their sides and/or incorporated into the brake lights or running lights. The flickering encodes an identifier, preferably the VIN (vehicle identification number), in binary format using a barcode type of encoding, ASCII, etc. The VIN is decoded by a detector. The detector may be coupled to a database to record a vehicle's identifier and/or to determine if the vehicle is stolen or wanted. If the identifier of a wanted vehicle is found, an alarm is sounded and/or information about the vehicle can be displayed. The flicker may repeat continuously or be repeated continually, at intervals. The intervals are preferably greater than the flickering duration, so that the flickers are spaced apart and therefore flickers from a group of vehicles will not overlap, permitting each vehicle to be individually identified without spatial localization.