In a method for adjusting a write strategy, data is written into the optical disc according to a first write strategy in forms of a first type of data storage structures with variable lengths and a second type of data storage structures with variable lengths. At least some of the lottery tickets in the game, whether printed or electronically simulated, can be provided with play indicia under a removable coating that indicates that the redemption value of that lottery ticket is variable. Each LED chip has an electrode that is inward biased at each end of the chip by a predetermined amount. A by-product film deposited on an inner surface of the reaction chamber is etched and removed by use of the cleaning gas thus supplied. The parallel plates have pairs of aligned holes in which a padlock can be inserted, preventing unauthorized removal of the device.