Spot is another perception content of Miarmy. It's actually a (position) point in 3d space.
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You can create spot in Miarmy > Perception Contents > Create spot or by shelf button 
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The spot is on LEFT(RIGHT) sentences will return the angle between the Z-axis of agent and the line of agent to the spots (angle between black line and green lines, shown as below). And then use these result determine agent at left or right.
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The spot is on LEFT(RIGHT) test spots in horizontal space whereas the spot is on UP(DOWN) sentence tests spots in vertical space.
spot is on LEFT(RIGHT) sentences example
The spot to me distance sentence will return distances between the agent and the spot in 3d space, like the following picture, the spot.d channel this sentence will return the input results [d1, d2, d3] from current agent.
spot to me distance channel sentence example