A puzzle requires drawing a full box with an X in the middle without taking your pencil off the paper. Normally, this would be impossible...but there Ain't No Rule that says you can't fold the paper over before you start to draw; with this trick, you just draw a square "C" over where the paper overlaps, unfold the paper so the "c" "breaks" into two horizontal lines, then draw an hourglass in the empty space, all without lifting up the pencil. A Variant: draw a circle with a dot in the middle without taking your pencil off the paper.
Since the exact dimensions the x in the middle of the box must be aren't specified, you can also get away with this one: Draw one side of a square and then draw a diagonal line, which will connect to the other end of the opposite side of the square, which you then draw. Repeat this on the other side to finish the x, and then complete the box by drawing the final two sides of the square, tracing over previously drawn lines to avoid having to lift your pencil.
In that case, you take a pencil, place it on a piece of paper, then casually whip out a pen with which you then draw the dotted circle... Without the pencil leaving the paper.
Alternately, use a mechanical pencil, draw a circle, press on the button to retract the lead, move to the center of the circle, press the button again to extend the lead, and complete the dot. That puzzle also makes no mention regarding overlapping lines, meaning you can draw the box, draw a diagonal from the last corner, retrace a side, then do the other diagonal.
It's not uncommon to encounter a number puzzle that has no solution unless you exploit the rules in this fashion. For example, there's a famous Henry Dudeney puzzle where you have to circle six of the following numbers to make a total of 21:
9 9 9 7 7 7 5 5 5 3 3 3 1 1 1
It can't be done as intended, because the total will always be even. Dudeney's solution? There Ain't No Rule saying you can't turn the paper upside-down first, letting you circle three 6s and three 1s.
A reader came up with an alternative solution; drawing a single circle around two 1s to get 11, then circling three 3s and the other 1.
The classic "nine dots" puzzle challenges you to connect a square of nine dots with just four straight lines without lifting your pen from the paper. It's impossible to do this unless you "think outside the box" and notice that there's nothing in the puzzle that forbids letting the lines run outside of the square.
Or you can fold the paper, use a very thick line, connect your four straight lines with a few curvy lines, etc.
Nobody said what shape it had to be, you can start at one corner, go out, go diagonal, go back, and go diagonal again.
Use a pencil.
Use a pen that isn't yours.
Tie a knot in a length of rope with both hands without letting go of the rope. There Ain't No Rule saying you can't tie your arms in a knot first (ie, fold your arms).
Or tie the knot around your arm, or tie an unknot, or stop holding it with one hand, but keep a firm grip with the other, and thus not letting go, or tying the knot in a different part of the rope, or don't hold on with your hands in the first place (but still use your hands in some other way) or hold the rope in a circle around you while tying a knot with a piece of string while inside the circle.
Most assume that the answer to the old brainteaser "Who is buried in Grant's tomb?" is Ulysses S. Grant, but the true answer is "nobody". While Grant and his wife are interred in his tomb, they are interred in above-ground sarcophagi. Thus, nobody is truly "buried in Grant's tomb".
One worksheet that is sometimes given to students in (usually elementary) school describes the classic "You are in a supermarket but find that your cart can only make left turns. Navigate the supermarket, getting everything on your list making only left turns"-maze scenario. There was no rule stating people can't draw a U-turn back to the start (where they get the cart" and write "Get a new cart that isn't broken."