MiniFrogCar

https://youtu.be/FjvrO9ZWBQU
This minirobot has two small geared motors and is brought alive by an ATtiny85 and a simple sketch:

int R = 0; //right motor
int L = 1; //leftr motor
void setup()
{ pinMode(R, OUTPUT); pinMode(L, OUTPUT); }
void loop(){
//forward
digitalWrite(R, HIGH); digitalWrite(L, HIGH); delay(1000);
//around left wheel
digitalWrite(R, HIGH); digitalWrite(L, LOW); delay(84);
//forward
digitalWrite(R, HIGH);
digitalWrite(L, HIGH); delay(1000);
// around right wheel
digitalWrite(R, LOW); digitalWrite(L, HIGH); delay(84);
}

An O-ring around the two wheels gives better grip. The third wheel is just a M3 bolt with a rounded nut.
The frog is decoration and can be found on Thigiverse.