辐射对称绘画

辐射对称是指各元素围绕一个中心点呈完全相同且对称的排列，例如雪花晶体的形状，或花朵中花瓣的分布方式。
我们先画出一个正方形，并作出它的两条中线与两条对角线；接着，在正方形的一个扇形区域内画出三条曲线和两条直线。这些线条先用软铅笔在描图纸上绘制，再将描图纸覆盖于正方形的每个扇形区域上，逐一描摹到画纸上。第一阶段完成后，便得到一幅辐射对称的图形，随后我们再用彩色记号笔将其重描一遍。第二阶段，我们仅选用4种颜色，用彩铅为图形着色，并注意使对称区域的颜色保持一致；同时通过调节彩铅的按压力度，营造出明暗变化（即明度层次）。本课由七年级学生完成，旨在引入“渐变”与“明度”的主题。

您还可购买配套打印版工作纸——其上已预先绘制好被分割为若干扇形的正方形区域，以简化教学活动。该工作纸亦可作为笔记本封面使用：

Drawings in radial symmetry

The radial symmetry has elements identical and symmetrical, relative to a central point, such as we can observe in the shape of snow crystals or in the disposition of the petals in a flower.
After drawing a square with its medians and diagonals, we have drawn three curved lines and two straight lines within a clove of the square. These lines were traced on tracing paper with a soft pencil, and drawn again on each sector of the drawing with the pencil. At the end of this first phase we got a drawing in radial symmetry, and we redrawn it with a colored marker. In the second phase we colored the drawing with colored pencils, choosing only 4 colors and paying attention to color the areas symmetrically. With colored pencils, we’ve created shades by varying the pressure of the pencil. We have created these masterpieces with the 7th grade classes to introduce the theme of the gradient and value.

You can also purchase the printable worksheet with a square area divided in wedge, to simplify the activity. The worksheet can be used as a notebook cover: