Article 90 introduces a 'pooling' system for the depreciation of machinery and plant. Assets are grouped into three pools with distinct annual rates: (1) 33% for computers, software, vehicles, heavy machinery (cranes, tractors), and furniture; (2) 10% for drilling rigs; and (3) 15% for all other machinery and plant not specified in the first two categories. This pooled approach simplifies tax calculations by applying a single rate to the collective value of similar assets rather than tracking each individual item's depreciation, facilitating easier compliance for businesses with extensive equipment inventories.