Look at the piece above. What type of medium was used to create this piece? How were the different values achieved? What makes this medium challenging?

The medium is pencil/pen and the different values were achieved by shading in darker areas dark and light areas lighter.this makes it challenging because with pencil/pen there can always over go with it

The vertical lines if trees

With the of an openoffice, sarah had to add a column chart in her math homework.