Group the given figures into three classes using each figure only once.

1, 6, 8 are figures composed of straight as well as curved lines.

3, 7, 9 are closed figures shaded by oblique line segments.

2, 4, 5 are figures composed of straight lines only.

1, 3, 6 contain one complete circle each.

2, 5, 7 contain a semi-circle each.

4, 8, 9 contain a triangle each.

1, 2, 7 are simple geometrical figures.

3, 5, 9 have one element placed inside a different element.

4, 6, 8 have two different elements attached to each other.

1, 4, 8 contain similar elements (not equal in size) each divided into four parts and attached to each other.

2, 5, 6 contain three elements (two of which are similar) placed one inside the other.

3, 7, 9 contain one element inside the other, which may or may not be similar.

1, 7, 9 contain two similar elements one inside the other but not touching each other.

2, 3, 6 contain two similar elements one inside the other and both touching each other.

4, 5, 8 are divided into equal parts by straight lines emerging from the centre.

5, 8, 9 are objects having both base as well as upper lid.

2, 3, 6 are objects having base but not upper lid.

1, 4, 7 tare objects which have neither a base nor an upper lid attached to them.

3, 6, 9 are geometrical figures containing line segments (the number of these line segments is half the number of sides in the figure) parallel to the sides of the figure.

1, 5, 8 consist of a circle and a triangle intersecting it. The triangle is also divided into two equal parts by a straight line.

2, 4, 7 are all funnel shaped figures.

1, 6, 9 are figures which are half shaded by slanting lines.

2, 4, 7 are all divided into equal parts (either three or four parts) by straight lines and also have a black circle at the centre.

3, 5, 8 have similar designs and have their four corners shaded black.