Adders

After the earth dries out, Noah tells all the animals to 'go forth and multiply'.
However, two snakes, adders to be specific, complain to Noah that this is one thing they have never been able to do, hard as they have tried.
Undaunted, Noah instructs the snakes to go into the woods, make tables from the trunks of fallen trees and give it a try on the tabletops.
The snakes respond that they don't understand how this will help them to procreate whereupon Noah explains: "Well, even adders can multiply using log tables!"