Fix the offsets to be applied to the flattened map.
Add new Jacobian computation for extruded element.
Modify rhs assembly to increment extruded maps correctly.
Add extruded map flattening and the appropriate offset increments.
Use non-flattened when assembling the LHS.
Add flattened and non-flattened case switching.
Fix extruded map dimension for flattened and non-flattened cases.