Of course I mean the digits on your hand, and not a binary counter, but the abacus is an important part of history and still in widespread use. There are several different configurations available. Mine, the one in the photo, is a Chinese abacus. The other popular one is the Japanese abacus, the Soroban. The number of beads on top and bottom may differ but the process remains the same. In most abacuses, the top beads, called the heaven beads, have a value of 5. The beads on the bottom, called the earth beads, have a value of 1. The place values read from right to left with the right most column being ones, then tens, hundreds, thousands, and so on. I realized that my photo is wrong as I wanted it to be all zeros, and that means that the 5 value beads at the top would be up, and not down on the center bar. 
The abacus can be used for more than simple addition, subtraction, multiplication, and division. It can be used to extract both square and cube roots. And, it is still taught in many Asian schools and can be faster than a hand-held calculator. There is also a great use for the blind, as the abacus is tactile and manual dexterity is  more important than visual acuity.
I am not proficient enough to provide a tutorial, but there are some really good sites with excellent instructions if you want to go further. Here is a good start with an amazing tool...

There has always been a fascination with glow in the dark phosphors, and the market for consumer products is quite large. The applications are very much varied from decoration to safety. And, manufactures have made a number of materials phosphorescent, from glow in the dark safety tape, to paint that can be used at home.
First, what is a phosphor and how does it work? Let's look at at a familiar concept to answer the question. A phosphor is a chemical that absorbs light in one frequency, or wavelength,and stores it as energy. It then releases that energy over time at another wavelength, or color. A good example is a fluorescent light familiar as a tube. It is a gas discharge tube that electrically excites mercury vapor to produce ultraviolet energy. The inside of the tube is coated with a phosphor that is quick acting, and converts the UV to a blue-white color. This is how the light is generated. But, there are slower release chemicals that store energy for a longer time. Zinc sulfide is one of the oldest materials that exhibits phosphorescence. It absorbs light in mostly the blue end or ultraviolet area of the spectrum, and releases its energy over time as a yellowish-greenish color. The problem with zinc sulfide is that it has a fairly weak color saturation, and a relatively short glow time. But, there are several newer materials that are available that have brighter color, and glow for ten times as long. Of particular interest is strontium aluminate. It is also greenish in color, and can glow for 8 to 10 hours after being exposed to light.

When I saw both the water-based latex glow paint from Rust-oleum, and the acrylic-based spray from Krylon, I was hoping that the phosphor being used was the strontium aluminate. But, neither container had the phosphor listed on the label, so I took a chance and purchased both for about $8 each.
I then followed the manufacturers instructions to the letter and expected at least reasonable results. The latex was coated on white foam board with six coats, and the spray with six light coats over a prepared piece of aluminum painted white as the instructions stated. Despite the carefully followed directions, the results were terrible. The two test pieces failed to glow after 8 hours in sunlight, or 10 hours under a fluorescent bulb. There was simply too little glow to even photograph the results. The only way to get any glow was to illuminate the samples with blacklight. And, as the photo will show, the glow is irregular, and looked like it was poorly mixed. The phosphor used is clearly zinc sulfide and had not lived up to the package claims. My recommendation is  to look for a glow paint that has the strontium aluminate, even if it costs more. Both packages advised that if I was dissatisfied, let them know. I am working on two emails right now! In the photo below, the latex is on the left.

This experiment is not necessarily for the birds, but, about the birds. I have been feeding the most common backyard birds that we have here in New Hampshire for a long time. It is fun to watch the behaviors and habits as they begin to get active in spring, and end most of the activity in early winter. I do feed during the winter, but with only limited occupancy. The most enduring guests are the woodpeckers, both the Downy and the Hairy, and their winter feeding of suet.  I make sure that even with 2 or 3 feet of snow, they get their winter nourishment.
But, because of my continuing curiosity about everything, I did have a question. Would the birds fly into an enclosed space to feed, despite the enclosure? So, after considering the question, I decided to build a mesh cylinder that would allow sight of the bird feed, but not an easy entry. I wanted the experiment to be safe for the birds and allow for several exits so they would never become trapped.
I made the cylinder out of vinyl coated ¼ inch hardware cloth, which is actually wire. The cylinder is 24 inches tall, and 15 inches in diameter. The base is ¼ inch Masonite pegboard that has been clear coated with acrylic spray to resist water damage. It should last for the duration of the experiment. There are three large openings, 4 inches by 4 inches that are big enough to get in and out easily. Each opening has a perch made with a 3 inch machine screw and covered with shrink tubing to permit good grip for perching birds. This will permit the birds to sit and look at the food without committing to actually going into the enclosure. The food is in a tray made from the bottom of a discarded plant container.
Of course, every experiment has to start with an hypothesis, and mine is that the desire for food will overcome the fear of enclosure. I already had a pole that is well hidden with foliage and will perhaps give them more courage, if birds get courageous.
I ran into several problems while setting up the test. First, I hid the enclosure in the foliage but the chipmunks found it first and cleaned out the food. So, I put the enclosure near the other bird feeders and the birds did land on the perches and look in, but failed to enter. Next, I removed the primary feeder and sure enough, they began to enter. The cover photo shows a sparrow chomping on some food. It began to rain so I replaced the regular feeder and will resume the test after the rain ends in 2 or 3 days. But, my original hypothesis was correct and the birds will enter for food under the right circumstances.
I added the build as a slideshow, but it is so straightforward that a similar one can be made with many variations. 

So, enjoy the show and always be curious. Thanks for checking out the post...