Everything you sketch on your flat paper is two-dimensional because it is flat. Is your paper, however, two-dimensional? It appears two-dimensional because it is so thin, yet it is actually a three-dimensional thing. If you were to slice your paper with a knife or pair of scissors, you would eventually reach bone.

Your paper has a three-dimensional structure that creates certain limitations on how you can draw on it. For example, if you were to use a pencil to sketch something on your paper, the line you drew could get thicker or thinner depending on which way you rolled it. If you were to roll the pencil straight down, then it would be more visible in the form of a threedimensional object.

Paper is used for drawing because it is easy to color. With **real objects**, you can only color **certain areas** because everything else is white or black. On paper, though, you can color anything that has texture or substance. A flat surface with **no details** cannot look realistic; therefore, it must be drawn as a piece of art.

What Is the Meaning of "2-Dimensional"? When a work of art is classed as 2-dimensional, it signifies that the composition has dimensions of length and breadth but no depth. Shapes comprise all 2-dimensional works of art, such as sketches, paintings, and prints. 3-dimensional works such as sculptures and models are shaped in **three dimensions**. Two-dimensional works can be further classified into line drawings and color photographs.

--from Wikipedia

2D means flat or planar. An image is considered two dimensional if it is composed of lines and shapes which only exist on **one plane**; there are no edges crossing from front to back or from side to side. Three dimensional images contain objects with height, width, and depth. Two dimensional images are easier to create because you don't need to worry about creating **realistic looking objects** that would appear three dimensional.

Three-dimensional things are solid forms. They are triangular in shape and have three dimensions: length, breadth, and height. They take up space in the cosmos because they are three-dimensional. Two-dimensional things are flat, and they only have two dimensions: length and breadth. Three-dimensional objects contain more space than they do matter, and so they weigh more than air or a gas. A volume of space equal to that of a cube has the same amount of matter in it as a volume of space equal to that of a sphere.

Things are solid if you can think that nothing but space is between their parts. A solid object takes up space and has weight. You can push on it and it will deform. It cannot be squeezed between your fingers but it can be crushed between **two heavy objects**. Solids include blocks, bricks, rocks, and minerals. Plants are solid substances that consist of cells filled with fluid. Your body is made of cells that are filled with fluid (blood, lymph, and other bodily fluids). This makes it solid enough for our purposes here. Humans are also considered solids because we are made up of **various solid organs** such as bones and muscles attached to each other with connective tissue. Solid substances are responsible for what we call "weight". Air is a gas that is light enough to float in. Water is a liquid that is heavy enough to sink in.

Make a 3D form. When you click anywhere on your page, your form will appear in the previously set dimensions, which are generally equal to or near to 1" x 1". You may also design your form with the necessary proportions by clicking and dragging. You may change the size of your form by clicking on it and revealing **the resizing boxes**. Click and drag any corner handle to resize your form.

What is the definition of **a two-dimensional shape**? A two-dimensional form is described in geometry as a flat planar figure or a shape with two dimensions, namely length and breadth. Two-dimensional, or 2-D, forms have no thickness and can only be measured on two sides. Three-dimensional shapes are those that have depth as well as width and length. 3-D objects can be seen from all angles, whereas 2-D objects can only be viewed from one direction.

Two dimensions vs three dimensions: It is important to understand that even though something may appear to have three dimensions, it may actually be two dimensional. For example, a sheet of paper has three dimensions (width, height, depth) but it is also two dimensional, meaning that it can be fully described by giving its size in **two dimensions** - width and height. A cube, on the other hand, is three dimensional; it has length, width and height. Even though it appears to have depth, a cube can still be considered two dimensional because there are only two ways to view it - front-to-back or side-to-side. A sphere is three dimensional; it has diameter, radius, and volume. However, it is also two dimensional because there are only two ways to view it - face-on or back-on.

The term "two-dimensional" may also be used to describe **any object** that can be viewed from only two directions at once.

Faces and flat surfaces are both possible for solids. These are the two-dimensional parts of **a three-dimensional object** (TEKS K. 6C.). A cube, for example (picture a tissue box), is made up of squares, which are the two-dimensional component of **this three-dimensional structure**. The sides of these squares are all equal in length; therefore, it is a square solid.

The other type of solid is the cube. This would be a solid with no flat or smooth surfaces. All of its faces are cubes - that is, they are all identical squares. There can be no pattern on the face of a cube solid. It can be any color or texture, but it must be uniform to be considered a cube solid.

These are just two examples of solids. You will learn more about different types of solids in your TEKS lessons.

Now that you know what a solid is, let's look at shapes in general.

Shapes are three-dimensional objects that have dimensions. Dimensions are the distance between **two points** on the surface of the shape. There are seven different kinds of dimensions: length, width, height, depth, radius, arc, and angle.

Length is the longest dimension of an object. In other words, it is the direction that is perpendicular to the page or screen when viewing a picture or drawing.