Each area on the board has an income. The income of an area can be seen at the upper left corner of the areas <l:hb_windows> and is counted in Production Units (Pu). At the beginning of a player's turn, the income of all his areas is summed up on the player's account. The player will then be able to buy <l:ha_equipment> costing up to the maximum of the Pu's on his account.
