
The Optical Mouse (1981) [pdf] - dangelov
http://bitsavers.trailing-edge.com/pdf/xerox/parc/techReports/VLSI-81-1_The_Optical_Mouse.pdf
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gojomo
Skimming the referenced PDF, it discusses the optical mouse peripheral, _not_
the onscreen pointer. (There is one illustration of an onscreen pointer in the
classic tilted-arrow form, but as an example of something already extant.)

The alleged "turn it 45 degrees, making it easy to see" rationale is only in
surrounding modern text (at these blog posts and the StackExchange answer). It
might be right, but if so, it's not supported in the linked 1981 document.

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dangelov
You are right. I just read the whole PDF (admittedly should've done it before
posting, instead of just skimming) and there is no mention of how the pointer
displays on the screen.

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userbinator
There's also the fact that an upward-pointing (or any other 90-degree
direction) pointer quite strongly evokes _direction_ instead of just
_pointing_ , while other not-aligned directions evoke pointing more than
direction.

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hoektoe
Relevant Question regarding this in UX Stackexchange,
[http://ux.stackexchange.com/questions/52336/why-is-the-
mouse...](http://ux.stackexchange.com/questions/52336/why-is-the-mouse-cursor-
slightly-tilted-and-not-straight/52338#52338)

~~~
beaker52
The guy stole my answer :(

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nicesanta
There has recently been a discussion about this here:
[https://news.ycombinator.com/item?id=7251987](https://news.ycombinator.com/item?id=7251987)

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chiph
I thought it was tilted so you could get the maximum "tail" length in a
smaller bounding box, because you are using the hypotenuse.

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krisgee
Completely spit balling here but wasn't the abstraction of your cursor
originally a finger? If so the 45 degree tilt with the 'finger' pointing to
the left makes sense if you just reach out with your right hand and point at
something on the screen.

At least for me when I'm pointing at a regular computer monitor my hand is
tilted not strait up and down.

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CmonDev
This is not an explanation. The only thing you can say is that the first mouse
pointer was _also_ tilted. The motivation can be different while result is the
same over time. Please don't upvote that superficial answer on SO UX.

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tracker1
Wow, just how many concepts from Xerox PARC have made other companies (MS,
Logitech, etc in this case) insane amounts of money.

