PEST3: My testing exercise

The exercise I presented at the last peer conference (PEST3) November  24 looks like this:


Note: If you want to solve the puzzle by yourself, do not view the comments as these may contain spoilers! If you have thought of some solutions but want help with the rest of them, contact me on Skype (SkypeID: onlyonejerru). You can ask questions to get more information and keep figuring it out until you have covered the solutions I have listed. Please include an explanation in the contact request. Also, I  won’t answer immediately if I don’t have time, so please be patient.

Mission: Replicate the drawing you can see in the image above. Draw a circle and a dot in the middle of the circle so that you do not break the contact between the pencil and the paper, and so that there is not connecting line between the dot and the circle.

How does this help to teach testing? This exercise is mostly about asking questions about the assumptions one makes when they see it, and the courage to experiment. I initially had one solution in mind but this exercise actually gets people quite creative as I’ve seen. I think  I know around 5-6 solutions for this by now.

Yes, it is an exercise in the size of a snack. However, I guess a test lead can appreciate a small exercise to do with their team that won’t take too long, and that they can modify as well (I’ll write about this later).

Are you up for a challenge? Let me know how you would solve this in the comments. I’ll publish the solutions I know of later, and if you offer a solution I didn’t know, I’ll list it along with others (credit is due).

P.S. I have not restricted to conditions for the exercise to a great extent deliberately.


10 thoughts on “PEST3: My testing exercise

  1. Offhand:

    – I could use two pencils at the same time. If I connect them together, I can twirl them like a compass and draw both the circle and the dot in the same action.

    – I could carve the tip of one pencil so that it has an outer circle as well as an inner tip. Then just touching it to the paper would make this shape.

    – I could draw a giant shaded circle and then erase the inner part. Similarly I could draw a dot, a line to the outer circle, and then erase the line

    – I could draw a dot, then tilt the pencil so that the lead of the pencil is not contacting the paper but the wood of the pencil IS in contact, then I could move it out and draw the circle.

    – I could draw on a surface that isn’t paper, while wrapping the pencil in paper. Thus I can lift the pencil without breaking contact with the paper.

  2. Some others:

    – I could draw the circle then fold the edge of the paper over to lift the pencil up, move to the centre and drop to draw the dot.

    – I could use a pencil with a retractable lead: extend the lead, draw the circle, withdraw the lead, move to the centre while still touching the paper, extend the lead again, draw the dot.

    – I could use a giant rubber pencil and have the non-writing end touching the paper at all times. (

  3. 1 more:

    – fold a narrow piece of paper into 3 layers like this: ___ L Z z ▂_, draw a point on the ridge where upper and lower layers are touching, release fold and continue to draw circle around the just-released point

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