1 summary

2 brief introduction

1 simple

2 not complicated

1 simply

2 at all

3 practically

1 to lengthen and shorten

2 flexible

3 adjustable

4 retractable

5 extensible

6 telescoping (collapsible)

1 to compress

2 compression

1 crude but simple methods (idiom); use whatever methods you can

2 to do things simply and thriftily

3 It's not pretty but it works.

1 to shrink back in fear (idiom); too cowardly to advance

1 to save on food and clothing (idiom); to live frugally

1 brief and to the point (idiom)

2 succinct

1 bound hand and foot (idiom); constrained