Funny stuff from art

For the difference command to work, what needs to happen?

In russian churches the number of domes usually matches the number of altars. but this church has only one altar dome, and 21 symbolic ones. what normal construction device does this church lack?

Need some ! asap i need to figure out 3 major changes in bridges over time and why these changes to adapt to both improvements in technology and changing social links would also alot.