What kind of graph is this?

I have posted this question in the SPSS part of the forum previously, but would like to repost it here, because it is not specific to SPSS.

Please see the two attached images.
My main question: How are graphs such as these made?
The graph labels are in Norwegian, please see the bottom of this post for an explanation.

More information about our data:
My team has a 6-month dataset of individual patients in the emergency departments of three hospitals. Variables include demographics (sex, gender), time of arrival and departure (and thus length-of-stay), and which diagnoses the patient received. In addition, we have registered the triage category, which reflects the degree of emergency (red is most urgent, followed by orange, yellow and green).

We have performed simple analyses such as median length-of-stay at the three hospitals, categorized by groups of diagnoses, and categorized by triage category.

We now want to analyze variations of the length-of-stay. Our questions include:
- [Graphical representation] How does the length-of-stay vary during the day and week?
- [Graphical representation and/or table] How does the number of patients that are in the emergency department at the same time, affect length-of-stay?
- [Regression?] What are the most important factors contributing to a long length-of-stay?

Translation of the graph labels:
The first graph shows median length-of-stay in hours (y-axis) for the four triage categories, on each day of the week (x-axis). The second graph shows number of patients (y-axis) on each day of the week (x-axis), and the colors represent percentiles for the study period.