Graffiti.
YES! it was used to keep away unwanted visitors and invading armies
The cell wall is a non-permeable membrane which helps to stop the entering of unwanted materials
Brian Wall has written: 'Wall's eye'
Shazreh Hussein has written: 'Unwanted & unloved'
Peter Conway has written: 'The unwanted child'
Robert Bluford has written: 'Unwanted pregnancy; the medical and ethical implications' -- subject(s): Abortion, Induced Abortion, Unwanted Pregnancy
Sumati Kulkarni has written: 'Wanted and unwanted fertility in selected states of India' -- subject(s): Birth control clinics, Family size, Fertility, Human, Human Fertility, Pregnancy, Unwanted, Unwanted Pregnancy, Utilization
The slang written on the wall means that something is in plain sight. When things are written on the wall, they are there for everyone to see.
Juliette Wall Pope has written: 'A George Willard Wall memorial'
Dorothy Wall has written: 'Blinky Bill'
Rob Wall has written: 'Corporate Warrier'
Benjamin Wall has written: 'Managerial economics'