Why the thin black curtain on the window?

Thoughts:

1. To block some sunlight from getting in.

2. It’s a secure facility and wanted to prevent people from looking in.

3. To not have to look at something outside.

4. It’s a secure facility and wanted to prevent the chance of taking a picture of someone or something outside that could compromise the location of the computer or someone’s identity; sometimes the first place a photogenic computer was built was at a customer site.