A journey is made up of different legs: just like giving directions.
First you go to the post office, then turn left until you come to the house with the red gate, walk another eighty metres, and it’s on your left.
Physics is simpler but more exact. Each leg is a straight line: set the direction and distance using the pucks.
Every journey is a collection of legs. To get curves, put in many short legs, with a small turn between each. If you’re not sure how this works, imagine walking along a curved pavement, step by step. Each step is straight, but you walk along a curve because you change direction a little each step.
See a journey from different points of view – remember it’s the same journey. Changing where you choose to see the journey from doesn’t change the journey.
Each point of view is a choice – you can’t choose not to have a point of view. Eventually, you’ll need ways to find out how a friend, who has chosen a different point of view records the journey. For now, you can switch to a different point of view in the diagram, and see how they record the journey.