cond marks the start of a gene in the DNA. Everything from cond to start is evaulated. Once the program reaches start, any values still on the conditions stack are anded together. If the resulting boolean value is true, every action after start to the next stop command is executed.
Otherwise, the program continues to the next cond statement, or stops reading the DNA if the endend is found instead.
The condition is the part of the gene that tells if should happen or not. Many action commands can be used in here but not all.