Boomerangs

The zigzag bullet flies in a curve, flying faster and faster.

There are 2 types of boomerang turrets, the straight firing kind and the split firing kind.

Tiers and Patterns

• Tier 1 (Figure 1): Launch 1 to 6 boomerangs forward.
• Tier 2 (Figure 2): Launch two groups of boomerangs forward, each group has 1 line, and each line has 3 to 6 boomerangs.
• Tier 3 (Figure 3): Launch two groups of boomerangs forward, each group has 2 lines, and each line has 3 to 6 boomerangs.
• Tier 4 (Figure 4): Launch two groups of boomerangs forward, each group has 4 lines, and each line has 3 to 6 boomerangs.

https://gamefaqs.gamespot.com/iphone/193681-phoenix-ii/faqs/76704/invader-weaponry#boomerangs