The more elaborate road blocks consisted of sandbag-camouflaged concrete slabs with peepholes. In addition, peepholes were found in bathroom stalls and shower walls. Althea notices one of the many peepholes Ronald has drilled. Such peepholes were also used in "isinglass curtains" in horse-drawn carriages and early 20th-century cars. The police also noted that peepholes had been drilled into the dressing rooms. Around the grid were vertical screens of canvas that had peepholes cut into them. The museum is accessible 24 hours a day via peepholes in its door. Simple peepholes may allow people outside to see inside.