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In my home is a common household object. I securely attached a marking pen to some point on the household object, and I placed a sheet of graph paper next to the pen, so the paper would not move. I then operated the household object in the normal manner, and it drew the pattern below. What is the household object?

Notes: My marker did not draw smoothly, but under perfect conditions, the curve would be smooth (not wavering), point A would be vertical at the end, and point B would be horizontal at the end.

curve on graph paper

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    $\begingroup$ Does this household object have fixed movement, with this being the only pattern it creates? $\endgroup$ – Ahmed Aug 21 at 17:00
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    $\begingroup$ The object has fixed movement, and the resulting pattern depends on where you mount the marking pen. $\endgroup$ – FlanMan Aug 21 at 17:37
  • $\begingroup$ Is the movement of object from A to B or it was B to A? $\endgroup$ – Mea Culpa Nay Aug 21 at 17:55
  • $\begingroup$ The movement of the object can be from A to B or from B to A. It goes back and forth. $\endgroup$ – FlanMan Aug 21 at 20:03
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    $\begingroup$ Do you have a cat ? $\endgroup$ – Criggie Aug 22 at 10:54
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A marker could have been attached to one of these:

bifold closet doors

enter image description here

Or maybe near one end of this?



enter image description here enter image description here

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    $\begingroup$ All hinged doors open in a circular arc. From this angle, it seems that the arc is the same as the one in the question but the drawn arc would be different. $\endgroup$ – Ahmed Aug 21 at 16:39
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    $\begingroup$ @Ahmed_Rahat depends on the placement of the pen. I don't think it is circular if it was somewhere on the right section $\endgroup$ – Adam Aug 21 at 17:25
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    $\begingroup$ @FlanMan Yes, bad drawing on my part, see the new image. $\endgroup$ – Chowzen Aug 21 at 17:49
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    $\begingroup$ @Chowzen The closet door solution is correct. I cannot determine if the garage door solution also works. Can you post more info, showing the point where the marking pen would be mounted, and the path of that point? $\endgroup$ – FlanMan Aug 21 at 20:59
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    $\begingroup$ @FlanMan Your comment inspired me to dust off my Algodoo program. See the updated picture $\endgroup$ – Chowzen Aug 22 at 3:03
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Did you

Attach the pen to another pen, and then draw a curve?

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The pen could have been attached to the side of the projecting footrest of a 'La-Z-boy' type recliner (on the lever side). When the lever is moved to lower the footrest, the path of the pen is like your A to B (grid in inches).

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Was it:

One of those oven doors that slides under the oven as you open it like the image below (without actually sliding it all the way in once it was horizontal)?
In this case the arc of the door opening would shorten in radius as the door slides under during the pivot stage. The line drawn would be that of a pen attached in line of the top edge of the oven door.

Image:

enter image description here

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    $\begingroup$ No, that's not it. It looks like your object has to fully open before it slides under, which would draw an arc, then a straight line, and not the requisite pattern. $\endgroup$ – FlanMan Aug 21 at 15:47
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The common household object could be

a vacuum cleaner.

As,.

it was operated in a room, filled with a thick layer of dust. The starting position is shown by A( vertically above B, because of dust) and as the cleaning gets completed, the pen's height decreases and settles down at B.

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If you used this for just a moment, slowly:

A cake mixer. It has a rotating blade attached to a rotating disc, such that the blade focuses on a different area of the bowl each moment. The two rotations are of different radius and speeds, allowing for a spirograph like image, of which we can only see the beginnings of. electric cake mixer in action

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