I can't figure out what that one is supposed to mean!

  In short, we’ll trade you iCloud for something great.

Love this subtle dig at iCloud.

You make it sound like it was a choice they made.

I took a class that explained light field photography, but I thought understanding the concepts through static diagrams was difficult. I made a little Mac app that simulates a 2D scene of light sources, lenses, and light-field sensors. The sensors shows their captured output in a graph.

The source is at https://github.com/bridger/optic-workbench

A bit of explanation (and a link to the pre-built binary) is at http://www.bridgermaxwell.com/index.php/blog/optic-workbench....

(Sorry it is only for Macs. I would love to redo it in Javascript someday, once I know Javascript.)

When I was doing this exercise with a friend on Understudy, he found solutions to multiplication and exponentiation too. I'm still trying to wrap my head around the exponentiation. Passing a number to another number?!

  (define (multiply number1 number2)
    (lambda (f)
      (number1 (lambda (x) ((number2 f) x)))))
  
  (define (exponentiate base exponent)
    (exponent base))

Let's use "twice" as the name of Church numeral 2, and "thrice" as the name of numeral 3.

If you look at the input and output of thrice, it looks like this:

   (function that gets applied once) -> (function that gets applied 3 times)

What if we used the output as the input again?

   (function that gets applied once) -> (function that gets applied 3 times) -> (function that gets applied 9 times)

We have a name for what we just did to the "thrice" function, and that name is "twice". So that's (twice thrice), and we can see it makes something happen 3^2 = 9 times.

I've been making a homemade version of Soylent (http://www.cookingfor20.com/2013/06/18/hacker-school-soylent...) since September. It makes up one or two of my meals each day. I've got to say, I really really like it. I think it has a good chance of catching on. I still love eating out socially, but it has replaced all my my mediocre meals. I can imagine it replacing those aisles and aisles of junk, easy food (cereal, canned soup, mediocre pasta).

That said, I quickly had to come up with a better name than Soylent. I call mine Science (for human consumption). It makes it distinct from food. "Did you get lunch?" "No, I just had Science today."

I am doing the chapter on register machines now. I love the diagrams that show the controller and the data path of the machine. See http://sarabander.github.io/sicp/html/5_002e1.xhtml#g_t5_002...

Scratch and Quartz composer show code in a graphical way. Are there examples of languages that show the data path in a similarly graphical way?

I would love to see how variables relate to each other and other functions (the data path) separated from the order in which these operations actually happen (the controller). It would be an interesting way to debug. For example, variables that get assignment but are never read would be glaringly obvious.

While it's very purpose specific, you might check out Unreal Engine 4's visual scripting in Blueprint.

https://docs.unrealengine.com/latest/INT/Engine/Blueprints/U...

For a quick primer: white connections represent the flow of execution, and have a variety of flow control nodes (Switch, Gate, DoOnce, etc) to direct execution around the graph. The other color coded lines represent the usual int/float/bool/string types, as well as some specialized things like rotators/translators/objects.

The debugging is fantastic, and sounds like something you might be interested in. You can set breakpoints on nodes and step through execution. Hovering the mouse over any variable will tell you what it's currently set to, or you can mark a value to be displayed next to its node in the graph. Take a look here for more: https://docs.unrealengine.com/latest/INT/Engine/Blueprints/U...

You'd need a $20/month subscription to get UE, but you can cancel it immediately if you don't mind not getting updates.

I can certainly see those as the next texts that we add!

I tried to tutor my niece in math using Google Hangouts and various whiteboard apps, but drawing with the mouse / trackpad was pretty difficult. Now we use Understudy and it works great, if I do say so myself.

You and your neice could both buy monoprice drawing tablets for the cost of a year of understudy. And it would be usable for any learning.

I am the other guy working on Understudy. The iPad has been the best platform for Understudy so far, but I still have my fingers crossed that Apple builds a better touch screen into their next iPad. Who should I pray to for that wish?

They don't need to build a better touch screen... they just need to add wacom or ntrig digitizer layer with a stylus. Think: Macbook Air with a flip or detachable screen and wacom baked in. This would probably vaporize the iPad as the duality of fully tablet and fully laptop negates the need for both. I like my MBP, but I am seriously considering a Surface Pro so I can get the tablet form factor and a full PC in one. The added bonus is handwritten notes and practicing digital art which used to require a Cintiq or another peripheral device.

Philipp Schmidt is a big proponent of peer-to-peer learning, and he calls it a pyramid scheme himself. :P http://dmlcentral.net/blog/philipp-schmidt/great-peer-learni...