@MaElena - Thank you for posting your query. I believe this is built using Bar Chart and transparent images in the Free - Form Layout Mode. You can see the Free Form Layput examples provided in Demo Central to get an understanding of the same. Sharing one of the similar report links for your reference. Hope this helps!
thanks just what i needed
Glad that you got what you were looking for. May I request you to please mark the relevant post as Solution so that the community can benefit from this if they have similar queries. Thank you!