What is the reason for the garland to be partially unlit?

What is is the the reason reason for for the the garland garland to to be be partially partially unlit?

18ko
 
What is the reason for the garland to be partially unlit?
Source
What is the reason for the garland to be partially unlit? - My, Electricity, Electrician, Repair of equipment

Repairers Community - Help Repair of equipment Electrician Electricity
v20260923a