Children with expressive language disorder have difficulty conveying or expressing information in speech, writing, sign language or gesture. (For preschool children, the difficulty expressing themselves in writing is not evident, as they have not started formal education.)
A rectangle is defined as a parallelogram (a quadrilateral with two sets of parallel sides) with the non-parallel sides joining perpendicularly (at 90Â°). A square is a rectangle with the additional constraint the all four sides be of equal length.
1 You can fit a square in a rectangle whose width is the same as the width of the square given that the length of the rectangle is longer than the width.  The second is the Fibonacci rectangle. This special rectangle adds the requirement that the length to width ratio be 1.618.