Cut top off T-shirt and create a tube that fits around child, using fusible hem tape or glue to create a "seam," if necessary.
Cut 1-inch-wide strips from a second T-shirt or from scraps. Pull strips at both ends so that they stretch and roll into a cord. Fuse or glue T-shirt cording to top of tube to create shoulder straps.
Dye about one dozen T-shirt cords in a solution of 2 packets drink mix to one cup water for about 5-10 minutes. Remove and blot with paper towels; hang to dry.
With a marker, draw horizontal lines on the T-shirt tube 1 1/2 inches apart. Place cardboard inside T-shirt. Use hot glue to attach dyed T-shirt cords onto the lines drawn on the tube.
Find or make (with cardboard and duct tape) a square box with a lid that will fit around child. For an infant, the bottom of the box can be closed so that the infant can sit within the box. For an older child, leave the bottom of the box open for the child to stand and walk.
Wrap and decorate box with decorative paper, wrapping paper, or deconstructed gift bags. Use double-sided tape to attach paper and decorations to box.
Optional: To create inner liner of the box, cut four long rectangles from a plastic tablecloth. The rectangles' short edges should match the length of the top edges of the box; the long edges should be approximately twice the depth of the box.
Fold the rectangles and tape the raw edges to each top edge of the box. Thread a T-shirt cord through all the folded edges and use to cinch around baby's waist.
To make the hat, dye two coffee filters. Place one dyed coffee filter on top of a stack of plain white coffee filters. Punch holes on opposite sides of the stack; feed a T-shirt cord through each hole. Form a cone with leftover paper and secure to top of hat with glue or tape. Cut fringe into the second dyed coffee filter, roll up, and glue to top of cone.Tip: Trace half a coffee filter onto paper, cut out shape, and roll up to make a small cone.
One very large white T-shirt or two regular white T-shirts
Fusible hem tape or fabric glue
Scissors and/or rotary cutter with mat
Unsweetened flavored drink mix
Hot-glue gun and hot-glue sticks
Cardboard and/or existing square box
Decorative paper, wrapping paper, and/or decorative gift bags