
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
A robot starts at the origin of the number line and moves along the direction of the number line, following a pattern where it advances 4 steps then retreats 3 steps. The robot moves one step per second, each step being one unit length. Let $x_n$ denote the position of the robot on the number line at second $n$ (for example, $x_4=4$, $x_5=3$, $x_7=1$). What is the value of $x_{2007} - x_{2011}$?

Present the answer in LaTex format: \boxed{Your answer}
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