A mnemonic is to imagine a dot at the top left end of the w whose two forward slash parts become bolded, and the backslash parts of the w fade out, leaving the dot and two forward slashes. Those three elements fall down in line to form ● ▬ ▬.
Try for practice:
● ▬ ▬ ● ▬ ▬ ● r
c ▬ ▬ ▬ ● ▬ ▬
● ▬ ▬ ●● ▬ n ● ●●● ●●●
● ▬ ▬ ●●●● ● ▬ ▬ ▬ ▬ ▬ y