Robot-favicon:
https://flaticons.net/custom.php?i=6grSPpHGIEIAIZIG9h9YljJuV
Robot-Teacher:
https://pixabay.com/vectors/electronics-humanoid-robot-7173509
Blackboard: https://unsplash.com/photos/cGNCepznaV8
Hourglass:
https://flaticons.net/custom.php?i=6PWiPpHGIEIAIZIG9h9YljJuV
Infoicon:
https://flaticons.net/custom.php?i=jyEUNBUzIJIbIBI8QcXBRlosW
Infinticon:
https://flaticons.net/custom.php?i=lQ5cx8I3IZIkIlIV2Tplmb6I8
Bookicon:
https://flaticons.net/custom.php?i=6grSPpHGIEIAIZIG9h9YljJuV