This website shows images and video of the Arabic letters. It has two sections, one with the Arabic letters in their independent, unconnected forms, and a second showing the letters in all of their various connected forms. Both sections offer videos that show a calligrapher writing out each form of each letter. Videos of the connected letters include words that demonstrate the initial, medial, and final positions of each letter.
If two inscribed angles intercept the same arc, then the angles are equal. Drag the orange points to change the figure.
A dynamically simplified solar system is constructed from online data to explore the real solar system on many different scales.
The realistically scaled solar system is surprising because nothing is visible due to the presence of many different scales. That is why it is usually rescaled in animations or illustrations. This is nice but gives us a wrong sense of distances and sizes. This Demonstration is intended to show the solar system's different scales in their full glory.
Since it is hardly possible to see anything when the real scales are used, controls have been added to modify the sizes of the celestial bodies.