The look of the pools on the art work remind me strongly hydrotherapy pools for children who need speciific care, there are special centers providing this king of care for 5 to 15 years old childrens. This activity would be a perfect cover for child abuse.
Some link as examples :
https://www.enableireland.ie/services/service-centres/galway
https://www.wlch.org/hydrotherapypoolspa.html
https://www.munters.com/en/munters/case-studies/hillside-primary-school/