They are known as land art.
A comics even though these are old but there is some that are still being made today it gives you a visual and reading about what who where and why is happening.
Answer:
Tom's eyes started off as a black line, but later transitioned into empty, black sockets. He inherited this peculiar trait from his "mother", a bowling ball. In a second Tumblr post made after the end of Eddsworld: Legacy, Tom offers his intended explanation for his character's black eyes.
Explanation:
