So, at a time when the Germans were actually using Zyklon B regularly to rid clothing of lice in special fumigation chambers (chambers no one asserts were used for killing people), and when doing so, always used the manufacturer-recommended machinery for extracting (via heat) and introducing the resultant toxic gas into the chambers via blowers, you are suggesting that, when it came to gas chambers designed to kill large numbers of people, suddenly they couldn't remember that they had those machines set up in other rooms in the complex, and tried just tossing the Zyklon B pebbles in through ports in the ceiling??
