Exercise Five: Jesse Colin Jackson

An object I love is the STAEDTLER Mars technico 780 C lead holder. I have 4 of them. One I've had since 1996, and the rest I've acquired later. In each I keep a different weight of lead: 6H, 4H, 2H and HB.

Affordances are subtle yet clear. The knurled end gives a tactile indication of where to best hold the lead holder; the clip keeps it secure in my pocket protector (ha, ha). As we expect, the end serves as a push-button to advance the lead. More unusually, it also serves as a sharpener, a possibility subtly suggested by its size (the same as the lead) and clarified by a diagram on the Staedtler website.

When the end is depressed, the lead advances. One potentially problematic aspect of the design is that unlike most lead holders, the lead does not advance incrementally. Instead, the push-button opens the jaws at the end that grip the lead, allowing the lead to potentially fall out of the pencil (an expensive error, at 2 bucks a lead). Once learned, it becomes natural to guard against this with your other hand when advancing a lead, and the infinite adjustability allows the lead to be sharpened to both a sharp and rounded tip, but perhaps a physical constraint could be introduced that prevents the lead from falling out completely.

There's no way to automatically differentiate between the different weights of lead, as the only available colour is blue. I've added an ugly label made of masking tape to each, which provides crude visible feedback, but it's an ugly solution at best.

[Disclaimer: I'll concede that I don't actually use a lead-holder much anymore. So perhaps there's some wistful nostalgia in my praise.]

An object I hate is my Sony Ericsson W810i mobile phone. It seems clever, at first: I'm impressed with the fact that the camera elements are mapped to a conventional camera. To operate the camera, you turn the phone sideways, which places the shutter button exactly where you expect it to be. By taking advantage of my existing camera interaction model, Sony has made it easier to take pictures. . . if I could figure out how to turn the camera on. There are no physical constraints to keep me from pressing the buttons when the phone is in my pocket, and these affordances are way too small in the first place: I'm forever turning the walkman on when I want to answer a call, as the buttons for these functions are right beside each other.

The audible feedback is excruciating: why can't mobile phones come with a normal ring tone? Why does my phone have to sound like a cat? I know, I know, I can download new ring tones - perhaps one of you can show me how.