[Bill Hammack], aka the [EngineerGuy] is at it again, this time explaining how retractable ballpoint pens work. In this excellent video, he describes the simple (but remarkably sophisticated) ...
Though I had grown up seeing my dad always using them, my own obsession with fountain pens started a little over three years ago, when I ordered my first pen, a jade-colored TWSBI Eco. It made writing ...
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