Create a rectangle with the rectangle Tool (m). Use the size indicated in the image below.

使用矩形工具(M)绘制一个矩形，使用的大小如下图所示。

youdao

Pick the Rectangle Tool(M) and create two new shape, like the red ones shown in the first image.

选择矩形工具创建两个新矩形，正如下第一张图线色那两个一样。

youdao

Use the Rectangular Marquee Tool (m) to make a rectangle selection and fill it with white (3b).

使用矩形选框工具(m)建立选区如图(3 b)并填充白色。

youdao

Again, for those-- for whom this is blocked, I'm just dividing the rectangle into smaller squares which is to say that memory is addressable.

这是一整块的，我只是把它划分成一个个小区域,每个小区域都可以设定一个地址。

哈佛公开课 - 计算机科学课程节选