i am trying to build a jigsaw puzzle which has no lid and is missing half of the pieces. i am unable to show you what it will be, but i can show you some of the pieces and why they matter to me. if you are building a different puzzle, it is possible that these pieces won't mean much to you, maybe they won't fit or they won't fit yet. then again, these might just be the pieces you're looking for. this is summing up, please find previous editions here.

• the center of "why?", by alan kay. living organisms are shaped by evolution to survive, not necessarily to get a clear picture of the universe. for example, frogs' brains are set up to recognize food as moving objects that are oblong in shape. so if we take a frog's normal food - flies - paralyze them with a little chloroform and put them in front of the frog, it will not notice them or try to eat them. it will starve in front of its food! but if we throw little rectangular pieces of cardboard at the frog it will eat them until it is stuffed! the frog only sees a little of the world we see, but it still thinks it perceives the whole world. now, of course, we are not like frogs! or are we? highly recommended (pdf)
• "interface matters to me more than anything else, and it always has. i just never realized that. i've spent a lot of time over the years desperately trying to think of a "thing" to change the world. i now know why the search was fruitless - things don't change the world. people change the world by using things. the focus must be on the "using", not the "thing". now that i'm looking through the right end of the binoculars, i can see a lot more clearly, and there are projects and possibilities that genuinely interest me deeply", bret victor
• ivan sutherland's sketchpad, a man-machine graphical communication system, the decision actually to implement a drawing system reflected our feeling that knowledge of the facilities which would prove useful could only be obtained by actually trying them. it was implicit in the research nature of the work that simple new facilities should be discovered which, when implemented, should be useful in a wide range of applications, preferably including some unforseen ones. it has turned out that the properties of a computer drawing are entirely different from a paper drawing not only because of the accuracy, ease of drawing, and speed of erasing provided by the computer, but also primarily because of the ability to move drawing parts around on a computer drawing without the need to erase them. had a working system not been developed, our thinking would have been too strongly influenced by a lifetime of drawing on paper to discover many of the useful services that the computer can provide (pdf)
• "i got this wild dream in my head about what would help mankind the most, to go off and do something dramatic, and i just happened to get a picture of how, if people started to learn to interact with computers, in collective ways of collaborating together, and this was way back in the early 50s, so it was a little bit premature. so anyways, i had some gi bill money left still so i could just go after that, and up and down quite a bit through the years, and i finally sort of gave up", douglas engelbart