The reusable concrete form device especially provides for extreme portability due to light weight, easily assembled components, and tools used repetitively in the application of the forms, flexible forms, braces, and pegs of the device. The device further provides for exact positioning and for maintaining that positioning until desired removal. The sliding dovetail joints of the forms and braces provide this feature. The pegs are located into a surface such as ground, then selectively locked in position relative to each brace via pivot head lock screws disposed within each brace. The headed pegs removably pass through chambers within the braces and are locked in position via pivot headed lock screws. Concrete poured is thereby poured exactly as needed. Joiners with tails are used to also form sliding dovetail joints and to joint forms and flexible forms together.