By creating a simple yet visible signal of progress he's been able to get a regular stream of success (pun intended) in the last few weeks. (daddilife.com)
Can your behavior be influenced by subtle, barely visible signals, such as an emotionally charged image briefly flashed on a TV screen or roadside billboard? (sciencedaily.com)
This pigment is what darkens skin to form freckles and moles, creating a clearly - visible signal at the site of the implant, telling the person that something is wrong and they should visit a doctor. (newatlas.com)