IF-pin1.svg

First attempt. Too much detail.

IF-pin2.svg

Reduced detail by enlarging factory shape and removing door.

IF-pin3.svg

Aligned vertical edges of the roof to the pixel grid.

IF-pin4.svg

Made windows a bit shorter and adjusted position of the bottom row.

IF-pin5.svg

Moved windows and tested adding door back.

IF-pin6.svg

Adding the door back was a bad idea.

IF-pin6b.svg

Tried moving door to get rid of a blur caused by a fractional pixel.

Animation

This animation shows the progression of the SVG files used for the pinned tab.