All 16 words, sorted alphabetically. Group them into four categories of four.
The four category names, easiest to hardest. No words revealed yet.
Theme name plus one word from each category.
CRAWLING, FIRST WORDS, ROLLING OVER, and SOLID FOOD are all classic developmental milestones that babies reach in their first year of life.
BLACKBERRY, DISCMAN, DVD PLAYER, and PLASMA TV are all consumer technology products that were hugely popular but have since become obsolete.
APRIL SHOWERS, LIQUID SUNSHINE, SCOTCH MIST, and WET WEATHER are all expressions or euphemisms used to describe rainy or drizzly conditions.
CARAPACE (a turtle's shell), GAS STATION (Shell the brand), PASTRY CRUST (a pastry shell), and ROWING BOAT (a shell in rowing) are all things the word 'shell' can refer to.