Jazz Beat Crayon Lesson

Create a cheerful children's crayon drawing on white paper in a 16:9 frame, like a hand-drawn educational video keyframe about jazz rhythm. At the top, write a large colorful Chinese crayon headline in two lines: {argument name="headline text" default="爵士乐为什么要打2、4拍?"}, with each character in a different bright color such as purple, blue, red, green, yellow, and cyan, slightly uneven like a child wrote it. In the center-left, draw one smiling cartoon child with a round head, spiky black hair, huge circular eyes, a wide open magenta mouth, stick arms raised happily, a blue scribbled shirt, thin brown stick legs, and purple shoes. On the center-right, draw one black grand piano in rough crayon lines with its lid open, yellow scribbled strings inside, four visible legs, a keyboard showing 7 white keys and 5 black keys, and 3 small yellow pedals beneath it. The child reaches toward or plays the piano, creating a cute beginner music lesson feeling. Add a bold subtitle near the bottom over the drawing reading {argument name="subtitle text" default="我们确认一下打节拍的意义"}, styled as thick white Chinese characters with a dark blue outline and yellow emphasis on the first two characters. Use messy wax-crayon texture, simple childlike proportions, imperfect perspective, bright primary colors, and lots of visible scribble strokes; keep the background plain white with no extra objects.