Why did president andrew jackson devise the spoil system?

According to Andrew Jackson, he developed the spoils system as a means to ensure that there was a "rotation in office." He argued that completely changing the members of the federal government under his control would make sure that there were no individuals who stayed in office for too long.

However, most Americans viewed the spoils system as a means for Andrew Jackson to reward his friends and political allies with government jobs. Jackson often gave these jobs to individuals who helped him during his presidential campaign.

Where’s the diagrams?