All reduction buildings add their deduction percentage to that given by Pulley, Geometry and Spirit Level. This means the actual discount is an additional 1%per level of the reduction building, plus the reduction from the level of research you have completed. For example, a Level 1 reduction building combined with Pulley has a net of 3% reduction, with Geometry there is a net of 7%, and with Spirit Level there is a net of 15%. With the maximum level of reduction buildings (Level 32, 32% reduction) and Spirit Level (14%), the maximum reduction for that resource is 46%. This means you use only 54% of the original cost.
The constant exercises with the fireworks don't only light up the skies, but sometimes also the surrounding buildings. Our researchers, though, can only optimize the demand for sulphur, when they test new mixtures again and again.
Lenses and magnifying glasses don't only help our scientists to see clearly and find important papers on their desk, they are also necessary in order to invent all the new technologies that make us so proud. The optician keeps everything we need carefully stored in boxes, so less things get lost and the demand for Crystal Glass is decreased per building level.